Summary: When sending a WhatsApp message to a guest, you may see the errors such as "Message could not be delivered for an unknown reason. Please try again and if the problem persists, contact our support team." This article explains the most common reasons this happens and what to do next.
Permissions Required: Converser. Brand Admin or Location Admin if template creation and submission required.
Possible Causes
There are several reasons a WhatsApp message may fail to deliver. Work through each one below.
1. You are outside the 24-hour messaging window
WhatsApp only allows free-form (non-template) messages within 24 hours of the guest's last inbound message. Once that window closes, the conversation is locked and free-typed messages will not be delivered.
You may see the following error message:
"Message could not be delivered for an unknown reason. Please try again and if the problem persists, contact our support team"
In addition to this conversation thread event:
"whatsapp channel has expired"
Common triggers:
The guest sent their last message more than 24 hours ago
The conversation has been sitting unattended overnight or over a weekend
A staff member is following up on an older conversation without checking the timestamp
What you can do:
Check the timestamp of the guest's last inbound message in the conversation
If it has been more than 24 hours, do not type a free-form reply
Instead, select an approved proactive WhatsApp template to re-open the conversation
Once the guest replies, the 24-hour window resets and you can send free-form messages again
💡Info: If you do not have a suitable proactive template available, contact your AXP administrator to create one on AXP then submit to Alliants Support team for Meta to approve, via Help & Support tab on AXP.
2. You are sending a marketing template to a US or Canadian number (+1)
Meta does not allow marketing category WhatsApp templates to be sent to phone numbers with a +1 country code (United States and Canada). This is a Meta platform restriction and applies regardless of your account settings.
You may see the following error message:
"Message could not be delivered for an unknown reason. Please try again and if the problem persists, contact our support team"
Common triggers:
Sending a pre-arrival, promotional, or upsell message using a Marketing-category template
The guest has a US or Canadian mobile number (+1 prefix)
You are not aware of the template's category
What you can do:
Check the category of the template you are selecting with Alliants support team if you are not aware — it will be labelled Marketing, Utility, or Authentication
If the template is Marketing, you cannot send it to a +1 number — the message will fail
Switch to a Utility template if one is available
If no suitable template exists, contact the guest via a different channel (email, SMS, or phone call) and/or ask guest to message in first
Resubmit the template as Utility for Meta to approve by editing the wordings, following Meta's guidance.
ℹ️ Note: Resubmitting the template will need a Location Admin or Brand Admin to create a new template on AXP from Settings > Message templates. Please raise to your admins if you don't see Settings tab.
ℹ️ Info: You can resubmit a new template for approval on your Meta Business Portal > Settings > WhatsApp account > Whastapp manager, if your management team or marketing team have access to it. If not, please raise the new template submission request to Alliants team via Help & Support tab on AXP.
🗒️ Note: Template categories are set in Meta Business Manager and cannot be changed by your team. If you need a template recategorised, you will need to create a new Utility template following the guideline for Meta to approve. However, it is up to Meta to decide what the final category your template will be.
What to expect:
The restriction will remain in place until Meta lifts the pause
Updates will be shared as soon as more information becomes available, Further information on this pause can be found on the Meta website.
3. The guest has blocked your WhatsApp Business number
🗒️ Prerequisite: This cause only applies if the guest messaged you within the last 24 hours (i.e. the messaging window is still open).
If a guest blocks your hotel's WhatsApp Business number, all outbound messages to that guest will silently fail. WhatsApp does not notify you when a block occurs, so the failure can appear identical to other delivery errors.
Common triggers:
The guest previously marked a message from your number as spam
The guest no longer wishes to be contacted via WhatsApp and blocked the number
The guest switched to a new phone or number and blocked the old business contact
What you can do:
Check whether the message failure is limited to this one guest — if other guests are receiving messages normally, a block is likely
There is no way to confirm or lift a block from within AXP
Try reaching the guest via a different channel: email, SMS, or a direct phone call
If you believe the block was unintentional, you can ask the guest (via another channel) to unblock your WhatsApp number
4. The guest's phone number is linked to more than one profile
🗒️ Prerequisite: This cause only applies if the guest messaged you within the last 24 hours (i.e. the messaging window is still open).
If the same phone number exists on multiple guest profiles in AXP, Sunshine Conversations (the platform that powers WhatsApp delivery) may merge those records internally. When this happens, the original messaging ID associated with one of the profiles becomes invalid, and any messages sent to it will fail to deliver.
You may see the following error:
"Message could not be delivered for an unknown reason. Please try again and if the problem persists, contact our support team"
Common triggers:
A guest has checked in multiple times and a new profile was created each time with the same number
A guest's number was manually entered on more than one profile (e.g. a shared family number)
The brand does not have phone number uniqueness enforced, allowing duplicates to exist
What you can do:
Search for the guest's phone number in AXP to check whether it appears on more than one profile
If duplicates exist, do not attempt to resend the message — it will continue to fail
Raise a support ticket with your AXP administrator, including the guest's phone number and both profile links
The support team will investigate whether Sunshine Conversations has merged the records and advise on the resolution
5. A transient platform error from Meta or Sunshine Conversations
Occasionally, delivery failures are caused by a temporary error on Meta's or Sunshine Conversations' infrastructure. These are not caused by anything specific to the guest, the message content, or your account settings.
Common triggers:
A brief outage or degradation on Meta's WhatsApp delivery network
A timeout or retry failure on the Sunshine Conversations side
The failure appears suddenly across multiple messages and then resolves on its own
What you can do:
Wait 5–10 minutes, then try sending the message again
Check whether other messages to different guests are also failing — if yes, it is likely a platform issue
If the problem persists for more than 30 minutes, check Meta's status page for any reported incidents
If there is no reported incident and retries continue to fail, raise a ticket with your Alliants support team
6. Your WhatsApp Business number's quality rating has dropped
Meta monitors the quality and engagement of messages sent from your WhatsApp Business number. If too many guests mark messages as spam, or if your outbound message volume is unusually high, Meta may throttle or restrict outbound messaging from your number entirely.
You will see the following error message if hoover over the failed message:
"This Message was not delivered to maintain a healthy ecosystem engagement"
Common triggers:
Sending the same or very similar messages to many people (bulk/automation behavior)
Messaging people who haven’t interacted with you before, especially repeatedly
Including suspicious links (shortened URLs, unknown domains, etc.)
A high volume of marketing or unsolicited messages were recently sent to guests in a short time
Multiple guests reported messages from your number as spam
Your number's quality rating has dropped to Yellow or Red in Meta Business Manager
What you can do:
You will not be able to resolve this from within AXP — this is a Meta-level restriction
Slow down your messaging (don’t send many messages at once, retrying is counted as one send)
Personalize messages instead of copy-pasting
Avoid sketchy or shortened links
Stick to people who have interacted with you or opted in
Check your Account Status in Meta settings for any restrictionsContact your AXP administrator and ask them to check your number's quality rating in Meta Business Manager → WhatsApp Manager → Phone Numbers
If the rating is Yellow or Red, Meta will display the reason and recommended actions in that dashboard
Reduce the volume of outbound marketing messages and avoid sending to guests who have not recently engaged, to allow the rating to recover over time
💡 Tips: If it keeps happening even with normal use, it may be a temporary restriction, and it usually clears after some time.
💡 Info: Only Facebeook admins can check Meta Settings. Your marketing team shall have access to your property's Facebook account. Please reach out to your management team or marketing team for assistance. Alliants team not always have access to them.
7. The guest's phone number is not registered with WhatsApp
WhatsApp messages can only be delivered to numbers that have an active WhatsApp account. If the guest's number has never been registered with WhatsApp, the message will fail immediately regardless of the message content or template used.
Common triggers:
The guest does not use WhatsApp on their mobile number
The guest recently changed their phone number and the new number is not yet registered with WhatsApp
The number belongs to a device that does not support WhatsApp (e.g. a basic phone or a landline)
What you can do:
Do not attempt to resend via WhatsApp — it will continue to fail
Open the guest's profile → Operations → Conversations to see which channels the guest has previously used
Reopen the conversation from a channel that has worked before, such as email, SMS, or in-app messaging
If no previous channel is available, contact the guest via other channels, such as email, or phone to confirm their preferred contact method
Common Questions
Q: The error says "unknown reason" — can I find out the exact cause?
A: Not always from within AXP. The error message is a generic fallback from WhatsApp when no specific diagnostic code is returned. Your AXP support team can run additional checks to narrow down the cause — raise a ticket if the issue persists after working through the steps above.
Q: Can I resend the message after a failure?
A: Yes. If you suspect a transient error, you can try sending again. If the failure is due to a template restriction or the 24-hour window, you will need to use a different approach (see causes 1 and 2 above).
Q: What if none of the above applies?
A: Contact your AXP support team. They can check the delivery error logs and, if needed, escalate to 3rd parties for further investigation.
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