IT doesn’t throw an error code. actually I didn’t explain it quite right.
THe learn dash registration does create the user account, but the account gets created with a random WordPress password rather than the password the user requested as they created their account. Since the password is the random one, the system then can’t log the user in to complete the process. The user also later cannot log in to their account since it isn’t the password they requested. When turning off your plug-in wp user manager, the learn dash registration form works correctly and the account gets created with the user requested password and the system logs them on and moves ahead smoothly.
Somehow wp user manager is forcing other plugin registration forms to default to random WordPress password in the user account creation.
does that make sense?