Common mailbox problems
Cannot sign in, mail not arriving, messages coming back undelivered or a full mailbox — symptoms, causes and what you can fix yourself in Email Business.
The four most common problems, with a clear line between what you can fix yourself and what needs your domain administrator.
You cannot sign in
| Symptom | Cause | Fix |
|---|---|---|
| Wrong account or password | The part after @ is missing | Enter the full email address, not just the name |
| The password is definitely right and still fails | The password has been changed | Ask your administrator to reset it |
| Forgot password? clicked, no email ever arrives | That link only serves service administrator accounts | Only your domain administrator can reset a mailbox password |
Mailboxes have no self-service password recovery
This is where a business mailbox differs from a free personal one. If the password is lost, the only route is your domain administrator.
Mail is not arriving
Work down the list and stop at the first thing that looks wrong.
- Check Spam — wrongly filtered mail sits there; see Handle spam
- Search with the scope set to All Mail
- Ask the sender to read you the error message they received — it says where the mail stopped
- Pass that information to your domain administrator
If none of those four finds it, the message never reached your mailbox, and the fix belongs to the administrator.
A message comes back undelivered
| What the error says | Meaning | Fix |
|---|---|---|
| Address does not exist | The recipient address is mistyped | Check every character, the domain part included |
| Recipient mailbox full | The other side is out of space | Tell them through another channel |
| Rejected as suspicious | The receiving side distrusted the message | Drop shortened links and unusual files, then resend |
| Message too large | Over the 25 MB per-message limit | See Write and send a message |
The mailbox is full
A mailbox over its quota stops accepting new mail — senders get an error while you simply see mail stop arriving. Current usage is in the account menu, under Storage.
The three places that free the most space, in order:
- Trash — deleted mail keeps its space until it is deleted permanently
- Messages with heavy attachments — find them with advanced search and Has attachment
Still full after clearing all three? Ask your administrator to raise the quota.
A desktop or phone app stopped working
| Symptom | Cause |
|---|---|
| Endless password prompts right after you changed your password | The app still holds the old password — update it on every device |
| Mail arrives but nothing sends | Outgoing server authentication is off |
| Webmail works, the app does not | The network is blocking the mail port |
The server settings the app needs, with steps for Outlook, Thunderbird, Apple Mail and phones, are under Settings → IMAP/SMTP Configuration.