I am not able to send sms using my pre-registered alphanumeric sender id

If it was functioning before and then just quit, the problem likely isn't with your configuration. Error 5000 often pops up when the sender ID is either temporarily blocked or hasn't been authorized for the route you're trying to use.

Start by confirming that your alphanumeric sender ID is still approved and hasn't run out or been suspended by the operator. This can occur unexpectedly if there's a policy or template discrepancy.

Then, ensure the message content precisely matches the registered template.

A minor tweak in spacing or wording is enough to get the gateway to reject the message.

Make sure you're using the right route, too. Some sender IDs are restricted to transactional routes and won't work on promotional ones.

If everything checks out, reach out to your SMS provider's support team with the error code and the time it happened. Given that it was working fine last night, it's probably a backend or operator issue, and they should be able to confirm or re-enable the sender ID without much delay.

Hii @admin sellonify,

Thank you for reaching out to us regarding the issue of not being able to send SMS using your pre‑registered alphanumeric sender ID.
Error 5000 typically indicates a generic SMS delivery failure in Azure Communication Services (ACS), often linked to issues like carrier throttling, throughput limits, or sender ID restrictions when using pre-registered alphanumeric sender IDs.
Please follow the below resolution steps
Step 1: Verify Sender ID Status

• Confirm that your pre‑registered alphanumeric Sender ID is still approved and active on the operator/DLT platform.
• Sender IDs can get temporarily blocked or suspended due to compliance or operator policy changes.

Step 2: Check Template & Content Matching

• Ensure the SMS content exactly matches the registered DLT template.
• Even small differences, extra spaces, punctuation changes, or added characters—can cause Error 5000.
• If needed, compare the live message with the approved DLT template carefully.

Step 3: Confirm the Correct Route

• Verify that you are using the correct SMS route (Transactional/Service route vs. Promotional).
• Some sender IDs are restricted to specific routes and will fail if used on the wrong one

Step 4: Check for Operator or Backend Issues

• Since it worked last night, there may be a temporary operator or gateway issue.
• Such issues can cause sudden error codes even when configurations are correct.

If all the above checks are correct, please contact your SMS provider and share:

• Error code: 5000
• Timestamp of failure
• Sender ID used
• Message content (for template validation)

Reference:
https://learn.microsoft.com/en-us/azure/communication-services/quickstarts/sms/enable-alphanumeric-sender-id
https://learn.microsoft.com/en-us/azure/communication-services/concepts/service-limits#sms

https://learn.microsoft.com/en-us/azure/communication-services/concepts/service-limits#sms
Kindly let us know if the above comment helps or you need further assistance on this issue.

Please "upvote" if the information helped you. This will help us and others in the community as well.

Also, why do I have to pay for the support when the service has stopped working on its own? I had to upgrade from basic to developer-level support for this. If there was an error in my code, then I should at least get a proper error message so that I can debug. I don't even know if the issue is due to my code or your service.

Thanks for your note. The alphanumeric sender ID is for testing OTP text messages for an application. This is what was said in the application form and was never used for any other purpose. I hope there is no discrepancy there. It was being used for Australian and NZ mobile numbers, so it was within the zone. It stopped working on its own. Should I wait and try again?

i tried it again this morning using python test script, i don't get any exception error but i don't get any sms as well.