Just posted a topic FIVE times - after hitting "Post", I got this message ina new screen:
Ran into problems sending Mail. Error: 535 5.7.8 https://support.google.com/mail/?p=BadCredentials x4sm4209608pfx.106 - gsmtp
Never saw this before - thought it hadn't posted so I kept trying - duh. ::)
This forum is running a very old version of the forum software, and it isn't being maintained. The error is a bug; not your fault.