When I try to access web mail in the cpanel and get this message
A fatal error has occurred
Cannot write to cache directory /home/(yourusername)/tmp/horde
Details have been logged for the administrator.
This error may show if your account has reached its inode limit. The inode limit is the number of total files (including emails) that you may have on the account.
Storage space is unlimited on some accounts but the actual file number is capped at 200,000 files. If you go over this limit it can cause errors including being unable to receive emails.
Deleting extra files and emails can bring this number down. The number of files on your account can be viewed in your control panel under the "Statistics" sidebar.