Email Account Over Quota Can't Send – Fix in 2 Minutes

I get it – you're in the middle of something important and your email won't send. The error message says something about quota or storage. It's frustrating, but the fix is usually fast. Here's exactly what to do.

The Quick Fix: Free Up Space

Your email account has a storage limit – usually between 500 MB and 10 GB on shared hosting. When you hit that limit, the server stops accepting new messages. It also blocks outgoing mail because the sent folder needs space to store copies.

1. Log into webmail. Open your browser and go to https://yourdomain.com/webmail or the webmail URL your hosting provider gave you. Log in with the email address and password you normally use.
2. Check your quota. Most webmail interfaces show your usage at the top or bottom of the screen. In Roundcube, it's in the left sidebar. In cPanel Webmail, it's under "Disk Usage." You'll see something like "234.5 MB of 500 MB used." If you're at 100%, that's the problem.
3. Delete old messages. Go to your Inbox. Sort by date and find messages older than 6 months. Select them all – you can click the checkbox at the top to select all on the page, then scroll down and click "Select all x messages." Hit Delete. Do the same for Sent and Trash folders. Empty the Trash folder after you're done.
4. Delete large attachments. Look for emails with paperclip icons. Open them, download any attachments you need, then delete the email. A single 10 MB video file attached to a message eats your quota fast.
5. Try sending again. After you've freed up at least 10% of your total quota, send a test email to yourself. It should go through now. If it doesn't, log back into webmail and check your quota again – you might need to delete more.

Expected outcome: After clearing enough space, the email you were trying to send should leave your Outbox and arrive at the recipient. You'll get a success message in webmail, or the email disappears from your Drafts folder.

Why This Happens

Your email server (usually Dovecot or Courier) enforces storage limits. When you try to send a message, the server tries to save a copy to your Sent folder. If there's no room, it rejects the whole operation. This happens with SMTP – the protocol that handles outgoing mail – because the server checks your quota before accepting the message. It's a safety feature to prevent your account from totally filling up and breaking other things.

On cPanel servers, the quota is set in WHM under "Account Functions" > "Limit Mailbox Storage." On Plesk, it's in the subscription settings. Your hosting provider sets these limits. You can't change them yourself unless you upgrade your plan.

Less Common Variations of This Problem

1. You're Under Quota But Still Can't Send

Sometimes you check webmail and see you're at 80% – not full. But you still get the quota error. This happens when your mail client (Outlook, Thunderbird, Apple Mail) has cached bad data. The server sees your actual usage, but your client shows the wrong number. The fix: close your mail client, open webmail, check the real quota. If it's fine, try sending from webmail. If that works, restart your mail client and try again. If it still fails, delete the account from your mail client and re-add it. That forces a fresh sync.

2. Shared Hosting Server-Wide Quota

Some cheap hosts (especially ones using cPanel) have a total disk quota for your entire account – email, websites, databases, everything. If your WordPress site or file uploads eat up the space, email stops working too. Check your cPanel "Disk Usage" or Plesk "Statistics" to see if the whole account is over quota. If so, you need to clean up files elsewhere – old backups, unused plugins, large log files.

3. Catch-All or Forwarding Loops

If you have a catch-all address (catches all email sent to any address at your domain) and you set up forwarding to another account that's also over quota, you get a loop. The server rejects the incoming mail, which bounces back, fills up the catch-all, and then blocks outgoing too. Break the loop by removing the catch-all or forwarding rule, then free up space on both accounts.

4. IMAP Sync Problems on Mobile

Your phone's mail app might be storing copies of sent messages locally that don't count toward the server quota. But if you delete messages on your phone but they don't sync to the server (because of a bad connection or app bug), your quota stays full. Force a manual sync: turn off Wi-Fi and mobile data, open the mail app, then turn data back on. The app should refresh. If not, delete the account from your phone and re-add it.

How to Prevent This Going Forward

• Set up a quota warning. In cPanel, go to "Email Accounts" and click "Manage" next to your email. Look for "Quota Warning." Set it to send you an email when you hit 80% or 90%. Most hosts have this feature – they just don't advertise it.
• Upgrade your plan. If you regularly hit the limit, you need more space. Check if your host offers a higher-tier shared plan with bigger mailboxes, or consider a VPS where you control the limits entirely.
• Use a separate service for large attachments. Instead of sending 20 MB files as attachments, use a link service like Dropbox, Google Drive, or WeTransfer. Insert a link in the email body. That keeps your Sent folder small.
• Archive old emails monthly. Set a reminder on your phone: "First of the month: delete emails older than 6 months." Automate it if you can – some email clients have rules that auto-delete old messages. But be careful: only do this if you're sure you won't need them later.
• Monitor your usage weekly. In webmail, note your quota percentage. If it's climbing, figure out why. Maybe you have a newsletter subscription filling your inbox. Unsubscribe from those.

A quick note on the mail client side: In Outlook, you can check your mailbox size by right-clicking the account > Data File Properties > Folder Size. In Thunderbird, it's under Tools > Account Settings > Disk Space. These numbers match the server only if you're in IMAP mode. If you're using POP3, the numbers won't match – you might have plenty of server space but your local storage is full. Switch to IMAP if you can. It's more reliable for shared hosting.

Final thought: If you've tried all of this and still can't send, contact your hosting provider. Ask them to check the mail server logs for the exact rejection reason. They'll see something like "over quota" or "mailbox full" in the log entry. That confirmation tells you the fix is definitely freeing up space – you just need to find where the hidden storage is being used.