I'm having this issue recently with my vestacp installation. It is showing NO LANGUAGE DEFINED and it's not disk space as I have 20GB space remaining and not inodes. But I suggest it's permission and ownership issue as other websites are working on the server are working perfectly. What's the default ownership and permission for vest panel? And how do I set it? Thanks
Are you on Ubuntu? Is it a KVM/Dedi or an OpenVZ VM ? Please give some more details
I have checked the inodes, it's not full. I am on Debian 7. I have been able to resolve this issue a little. Instead of showing "NO LANGUAGE DEFINED", it's now showing "Incorrect username or password" while the details are correct. I'm able to login to SSH but not to vestacp.