API Configuration: Double-check all API endpoints and IDs in Fabric configuration.

Authentication: Verify credentials and token expiration for CMS access.

Launch Configuration: Confirm enableThirdPartyCmsIntegration is set to true. See "Enable Third Party CMS in Visual Builder Studio".

Network: Check for any network restrictions or proxy settings that might interfere. If the service implemented is deployed on a cloud platform or on premise, make sure it is accessible over the web and cater to the proxy configurations.

Logging: Enable debug logging in Fabric and Launch for debugging. You can raise an SRE Ops ticket to change the log level and get the logs.

Launch logs would only be needed rarely as you can get sufficient details about the request from network tab itself.

If everything from Launch side looks good, then the next logical step is to get the logs of RMS aka Routing MS. By default, the log level will be error. If the error or issue is not clear, get the log levels raised to DEBUG and then collect the logs. All this log collection and log level changing can be done via raising a ticket to the SRE Ops.