A bounce message — one with a subject like Undelivered Mail Returned to Sender, a sender named Mail Delivery Subsystem, or an address like mailer-daemon@… — is written by a mail server, not by BlueMail. It is the server's way of saying it refused a message and handed it back.
That matters for what you should do next. Because BlueMail did not produce the bounce, app-side fixes cannot stop it: reinstalling BlueMail, clearing the cache, or removing and re-adding the account will make no difference. The condition being reported lives on the mail server, so that is where it has to be fixed.
What the code in the bounce means
Bounce messages usually quote a three-digit code. These are the ones people most often see:
- 552 and 452 – The action was aborted because a mailbox is over its storage allocation. In plain terms, a mailbox is full.
- 550 – The mailbox is unavailable: not found, no longer in use, or rejected for policy reasons. Check the address for typos, and check that it still exists.
- 554 – Rejected by the receiving domain. This is a blanket "not allowed", and it is often about sending reputation or spam filtering rather than the address itself.
For the fuller list, see Understanding the SMTP Error Codes.
The same full-mailbox condition shows up under other protocols with different wording. OVERQUOTA in IMAP error codes and -ERR Disk quota exceeded in POP3 error codes are the same problem seen from your side of the connection instead of the sender's.
If the bounce is for mail sent to you, your mailbox is full
This is the part readers usually miss. If people writing to you get a 552 or 452, it is your mailbox that is over quota — and that is also why your new mail stopped arriving. The server has nowhere to put incoming messages, so it rejects them and returns them to whoever sent them. Both symptoms are one problem.
Free up space and delivery resumes on its own.
Free space in your provider's webmail
Do this in your provider's web interface in a browser, signed in to the affected account. Storage quota is set and counted by the provider, so the provider's own tools are what release it.
- Delete the largest messages first — anything with big attachments.
- Empty the Trash. Deleted mail still counts against your quota until the Trash is emptied.
- Empty Spam or Junk.
- Empty Archive, if your provider has one. Archived mail is still stored mail.
Two things that do not free server space:
- Clearing BlueMail's cache. Clear Cache frees storage on your device only. It never touches your quota on the server.
- Deleting in BlueMail alone, in some setups. Messages you delete move to Trash and keep occupying the quota until the Trash itself is emptied — see How do I empty all the emails in the Trash folder?. After emptying, check your usage figure in webmail to confirm the space was actually released.
POP3 accounts: mail can pile up on the server
If the account is set up as POP3, there is a BlueMail setting worth checking. Delete Messages on Server defaults to Never, which means downloading your mail into BlueMail leaves every copy on the server indefinitely. Over time that alone can fill the quota.
To see or change it:
- Go to Settings.
- Navigate to Accounts.
- Tap on your account.
- Select Delete Messages on Server.
The options are Never (the default), When deleting from trash, and When downloading messages. Details are in How to Delete Emails from the Server with POP3 Accounts?.
Choose carefully: once a message is deleted from the server, other devices can no longer download it. And whichever option you pick, clear the backlog that is already on the server from your provider's webmail.
Can BlueMail bring back a bounced message?
No. A bounced message never reached your mailbox — the server refused it and returned it to the sender, so there is no copy for BlueMail to fetch, restore or resend. Nothing in the app can recover it.
Once you have free space, ask the sender to send the message again. Mail sent from that point on will be delivered normally.
If nobody is getting bounces but mail is still missing
Then this is a different problem. Start with Missing Emails for mail that was delivered but is not where you expect it, and Connection Issues, Sync Failures or Missing Emails if BlueMail is not syncing with the server at all.
