Different logins for wp-admin and other wordpress.org functions?

Logging into my wp-admin has always worked seamlessly. What I am very confused about, is that this log-in doesn’t seem to be recognised in any other areas on wordpress.org. Example: I initially tried to log-into this forum to actually post something about another topic, but my log-in wasn’t recognised. Work-around solution: I registered as a new user. I 100% sure this isn’t the best solution though.

Is there something I’m missing?