A mailbox that reaches its assigned storage quota cannot receive additional mail. Account-wide disk exhaustion can also interfere with mail storage.
- Open cPanel Email Accounts and review the mailbox’s current storage usage and limit.
- Use Email Disk Usage to identify large folders/messages when available.
- Delete unneeded mail and empty server-side Trash/Junk folders as appropriate.
- If the mailbox has an adjustable quota, increase it only within the account’s available storage and any provider-defined maximum.
- Check Track Delivery after freeing space to see whether new messages are accepted.
cPanel documents that a mailbox with a full quota cannot receive mail.
