Hello reader,
If your Business Central extension makes outbound API calls and one day they all stop working with a cryptic error like the one below, this post could save you days of troubleshooting. It cost me plenty of time before I found the culprit, and the fix took less than a minute.
You get an error like this
The Symptom
An integration that has worked for a long time fails out of nowhere. Nothing in the code changed. The same request works perfectly when you send it from Postman, but from Business Central, HttpClient.Post() simply returns false. No HTTP status, no response, no useful log entry. The request never leaves the service tier.
The Root Cause
The "Allow HttpClient Requests" setting on the extension is turned OFF.
Every extension in Business Central has a per-extension permission controlling whether its AL code may make outbound HTTP calls. When it is off, every HttpClient call fails instantly and silently. The nasty part is that this flag can silently reset when the extension is re-published or upgraded, or when the environment is copied or restored. So a routine deployment quietly kills your integration, and the failure looks like an external API problem.
The Fix
- Search for Extension Management
- Locate your extension and open its details (or ... menu, then Configure)
- Switch Allow HttpClient Requests to ON
- Retry. No restart or re-publish needed
Lessons Learned
- After every publish or upgrade, verify the flag. Make it a deployment checklist item.
- Test the same request from Postman. If it succeeds outside BC but fails inside, suspect this flag before blaming the external API.




