"Disk quota exceeded" error when CPanel shows inodes used 0% (2 of 30019)

[anon11873966]

421 3900 users (the maximum) are already logged in, sorry (and file manager issues)

For a few days now, it appears that there are capacity issues on the FTP servers again. When trying to login to the FTP server, you’ll see an error like: 421 3900 users (the maximum) are already logged in, sorry The file manager, which also relies on FTP, is also unable to connect. You may see error like “Could not read line from socket” or simply be redirected back to a login screen. We’re aware of the issue and we’re investigating it.

… not sure if this one related to my problem… they discuss only FTP server functionality, it appears I have global write permission issue where FTP that unable to upload seems to be only part of the problem