Email Not Sending or Receiving? Check It in the Browser First

The webmail test

Open a browser and sign in to your provider's website directly — mail.google.com, outlook.com, or whatever yours is. Try to send yourself a message and see whether it arrives.

Works in the browser, not in the app

Your account is healthy. Something between the app and the server has broken — and this is far and away the most common category, because it usually happens overnight with no action on your part.

• You changed your password recently. The mail app still has the old one and will keep failing silently, sometimes without any visible error. Remove the account from the app and add it again.
• You turned on two-factor authentication. This is the classic. Many older mail apps cannot handle a second factor and need an app password — a separate generated password issued specifically for that app, from your account's security settings. Your normal password will simply be rejected.
• Your provider tightened security. Providers periodically stop accepting plain username-and-password access from older apps. If a mail client that worked for years suddenly can't connect, this is very often why. The fix is to remove and re-add the account so it uses the modern sign-in flow, or to switch to the provider's own app.
• Check the outgoing server settings specifically. If receiving works and sending doesn't, the outgoing (SMTP) settings are wrong — wrong port, wrong encryption, or authentication not enabled. Your provider publishes the exact values; copy them rather than guessing.
• Your network blocks it. Some public, hotel and corporate networks block outgoing mail ports to prevent spam. If sending fails only on one network, that's your answer — test on mobile data.
• The app is simply offline. Look for a "work offline" toggle, and check the app isn't restricted from using data in the background.

Not receiving anything

Nothing arrives, in the browser either. Work through these in order:

1. Check your storage. This is the most common cause and the least expected. When your account is full, incoming mail is bounced back to the sender — you don't get a warning in your inbox, because nothing can arrive. Our Google storage guide covers how to find where the space went; other providers have equivalent limits.
2. Check the spam folder, and any "Promotions", "Updates" or "Other" tabs your provider has invented. Mail is often exactly where you'd look last.
3. Check your filters and rules. A rule that archives or deletes matching mail will happily do so forever, and people forget rules they set up years ago. In Gmail: Settings → Filters and Blocked Addresses. In Outlook: Settings → Mail → Rules.
4. Check forwarding. If mail is being forwarded elsewhere with "delete after forwarding" enabled, your inbox stays empty. If you didn't set this up, treat it as a serious security signal and read our email compromise guide — a hidden forwarding rule is the classic trace a real attacker leaves.
5. Check your blocked senders list for anything added by accident.
6. Ask the sender what happened. Bounce messages contain the actual reason — mailbox full, address doesn't exist, message rejected — and that one line saves an hour of guessing.

Receiving some mail but not others

Selective failure points at filtering rather than a broken account.

• One specific sender never arrives. Search your whole mailbox — including spam and trash — for their address rather than scrolling the inbox. If it's genuinely absent, check your blocked list and your filters, then have them check whether their mail bounced.
• Mail with attachments doesn't arrive. Providers reject certain attachment types outright, executables in particular, and enforce a size limit — commonly in the tens of megabytes. Large files should go via a file-sharing link instead.
• It arrives, but hours late. Usually greylisting or a queue at one end, and it generally resolves itself. Consistently slow delivery from one particular sender is worth mentioning to them.
• You see it on one device but not another. That's a sync setting, not a delivery problem. Old POP accounts download and remove mail from the server, so whichever device checks first gets it and the others never see it. Switching to IMAP fixes this permanently.

Sending fails

Read the actual error rather than dismissing it — mail servers usually say precisely what went wrong.

• "Message too large." Attachment over the limit. Use a sharing link. Note that attachments are encoded for transit and end up roughly a third larger than the original file, so a file slightly under the stated limit can still be rejected.
• "Authentication failed" or repeated password prompts. App password or the modern sign-in problem described above.
• "Recipient address rejected" or "user unknown." The address doesn't exist — check for a typo, especially a wrong domain suffix.
• "Daily sending limit exceeded." Providers cap how many messages you can send per day to limit spam. If you hit this without sending much, someone may be sending through your account — go straight to the compromise guide.
• It sits in the outbox forever with no error. Usually the app is offline, or one oversized message at the front of the queue is blocking everything behind it. Delete the stuck message and see if the rest go.
• Sending works in the browser but not the app. Outgoing server settings. Get the exact values from your provider's help page.

Your mail arrives in other people's spam

A different problem with the same feeling of not being able to communicate.

• Ask the recipient to mark it "not spam" and add you to their contacts. This is the fastest fix and it works per-recipient.
• If you use your own domain, the cause is usually missing email authentication records — SPF, DKIM and DMARC. Without them, receiving servers have no way to verify the mail genuinely came from you, and modern providers are strict about it. Your mail host publishes the exact records to add to your DNS; this is a one-time setup and it makes a large difference.
• Check whether your sending address is on a blocklist, particularly if you share a mail server with others. There are free lookup tools for this.
• Avoid the patterns spam filters dislike: a subject in all capitals, lots of exclamation marks, a message that is one large image with no text, or link-shortener URLs.

Quick checks worth doing regardless

• Is the provider down? Check their status page or a third-party outage tracker before assuming it's you. Large providers do have outages, and there is nothing to fix on your end.
• Restart the mail app, and on a phone check that background refresh is allowed for it — otherwise mail only arrives when you open the app.
• Check the date and time on the device. A badly wrong clock breaks the encrypted connection to the mail server, and the resulting error rarely mentions the clock.
• Turn off any VPN and retry. Some mail servers refuse connections from VPN address ranges.
• Check for a second account with the same name. More than one person has spent a morning looking for mail sent to an address they no longer use.