Can't upload files to ftp due file quota exceed but in reality it isn't

I have stumbled across unpleasant problem, it’s letting me know once a while actually and disappears by itself? I have noticed a lot of people experiencing same issue? Is resetting website DB or deleting website is only solution to this? I am using wordpress and uploaded only 2 files before this error appeared.

Where is the error appearing; please screenshot and upload!
Many thanks.

Thank you for reply.
I created some screenshots for better understanding this hassle. It just randomly disappeared last time and I was freely uploading my files. But now it’s bothering again.

I guess this is due to the FTP issue.

Try again as it is working fine for me!!!

Thank you for answer

Do post back if you’ve any issues!!!