If you find your Posterogs account is suddenly banned and you can't think of any conceivable reason (we'll generally contact you before taking such action), it's likely that it's inherited from your Discogs account. Please check if you have a database ban or marketplace suspension on Discogs.
You'll need to resolve your account issue with Discogs in order to get full usability of Posterogs once again. This could be as simple as paying an oustanding invoice, or you may need to get in touch with Discogs support team.
Once the issue is resolved with Discogs, if you still have trouble accessing Posterogs, try logging out and back in again. This will reboot your account is necessary.