When executing /SDF/ALM_SETUP at least one HTTP destination is created. You can display them in SM59 (type G) with prefix ZSDF_<your destination name>.
When you need a proxy access with authentication a second destination ZSDE_ <your destination name> is created.
Don't manipulate the Path Prefix in SM59!
A connection check in SM59 with http status 400 is normal. Everything else e.g. 401 (wrong credentials) , 403 (forbidden), 500 (error) is not normal.
When clicking on register a synchronous call to the ALM platform is executed. If no LMS ID is retrieved and displayed the registration was not successful. There might be several reasons:
During initial setup you can specify in each client which data should be collected. However the ALM platform is the leading instance and a use case and a user can define there if data collection is not allowed anymore. In that case you cannot re-enable the data collection in /SDF/ALM_SETUP. It must be done in the central platform.
However you still have the possibility to disable data collection for some use cases.
Data collection is triggered periodically by the scheduled job CALM Scheduler <your name> (Report /SDF/CALM_SCHEDULER) as tasks via asynchronous RFCs.