An email waits in the Outbox until your provider's server accepts it. BlueMail keeps retrying on its own, and if it cannot get the message away it moves it to Drafts, complete and ready to resend, with a notice telling you so (more on the mechanics in What is Outbox Folder?). A message that sits in the Outbox through several attempts is not stuck for no reason. The server is rejecting it, and the first step is to find out why.
Step 1: look at the error
- Tap your account avatar at the top left and open the Outbox folder (navigating between folders).
- A message that failed shows a send failure state. Open it to see the error the server returned.
- Look the error up in SMTP error codes. Each code says what the server objected to.
The usual cause: attachments too large
If the stuck email carries attachments, size is the first suspect. BlueMail itself sets no attachment limit, and almost every provider caps the size of a single email, typically 10 to 25MB, and rejects anything bigger (SMTP errors 523 and 552 are both size rejections). Two things make this easy to hit:
- The limit applies to the whole email, not just the files, and email encoding inflates attachments by roughly a third in transit, so two 10MB files can already exceed a 25MB cap.
- The cap is enforced by the server, so nothing you change on your device helps. It fails on every retry until the attachments shrink.
What to do: remove or compress the attachments and resend, split the files across separate emails, or share big files as a link (Google Drive, Dropbox, OneDrive) instead of an attachment. BlueMail can shrink images for you as you send; see compressing images.
Other causes worth a minute
- Connection dropped mid-send. Switching between Wi-Fi and mobile data and letting BlueMail retry often clears it. See Phone Disconnects While Sending.
- The server is refusing your sign-in or settings. If every email fails, not just the big one, check the account's outgoing server settings.
