Outlook error fix · Classic Outlook (Windows)
Fix Outlook Error 0x800ccc90
Outlook error 0x800ccc90 means the mail server rejected your POP3 login — your username or password wasn't accepted. It most often appears right after a password change. The fix is to re-enter your full email address as the username, use the correct (or app) password, confirm port 995 with SSL, and make sure POP is switched on in your mailbox. Rated 4.9 on Google.
- ● Classic Outlook (Windows)
- ● POP3 login rejected
- ● Port 995 with SSL
What it means
What error 0x800ccc90 actually means
The message that comes with it is usually "Your incoming (POP3) server rejected your login." In plain English, Outlook reached the server fine — but the username or password it sent wasn't accepted, so nothing downloads.
Because it's a login problem rather than a connection problem, the usual triggers are:
- Your email password was recently changed and Outlook is still using the old one — by far the most common cause.
- The username isn't your full email address (some servers need the whole address, not just the bit before the @).
- Your provider (such as Gmail or Yahoo) now requires an app password because two-step verification is switched on.
- POP access is switched off in your mailbox's settings, so the server refuses POP logins entirely.
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Step by step
How to fix it in classic Outlook (Windows)
Work through these in order. If you know your password changed, start at step 2.
- Open your account settings. Go to File > Account Settings > Account Settings. On the Email tab, select your POP account and click Change.
- Check the username and password. Make sure the User Name is your full email address (for example you@your-domain.com, not just "you"). Then retype your current password carefully — a stale password after a recent change is the number-one cause of this error.
- Use an app password if your provider needs one. If two-step verification is switched on with your provider (such as Gmail or Yahoo), your normal password won't work here. Generate an app password on the provider's security page and paste that in instead.
- Confirm the incoming port and encryption. Click More Settings > Advanced and set the incoming server (POP3) to port 995 with SSL/TLS. Check the outgoing (SMTP) side too — port 587 with STARTTLS and, on the Outgoing Server tab, tick "My outgoing server (SMTP) requires authentication".
- Make sure POP is enabled in your mailbox. Sign in to your email provider's website and check that POP access is switched on in its settings — if POP is disabled there, no password in the world will let Outlook log in.
- Test the settings. Back on the change screen, click Test Account Settings. The incoming (POP3) test should now pass with a green tick.
Re-entering your password and correcting the port doesn't touch your existing mail. If we ever need to rebuild a POP profile, your messages already downloaded stay in your data file — we always back up first before any bigger change.
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// GOOD QUESTIONS
Frequently asked
Why does 0x800ccc90 say my POP3 login was rejected?
It means Outlook reached the server but the username or password it sent wasn't accepted. Check that your username is your full email address and retype your current password. If your provider (such as Gmail or Yahoo) uses two-step verification, you'll need an app password rather than your normal login.
It started right after I changed my password — is that why?
Almost certainly. Outlook keeps using the old saved password until you update it, and the server rejects it. Go to File > Account Settings > Account Settings, select the account, click Change and retype the new password. This is the single most common cause of 0x800ccc90.
Should my username be my full email address?
For most POP accounts, yes. Many mail servers expect the whole address (you@your-domain.com) as the username, not just the part before the @. If in doubt, enter the full email address in the User Name field on the account's Change screen.
Which port should POP3 use, and does it need SSL?
Use incoming POP3 port 995 with SSL/TLS for a secure connection. You'll find this under More Settings > Advanced. On the sending side, use SMTP port 587 with STARTTLS and tick 'My outgoing server (SMTP) requires authentication'.
What if POP is turned off in my mailbox?
Some providers disable POP access by default. If it's off, the server refuses every POP login regardless of your password. Sign in to your provider's website, open its mail or forwarding settings, and switch POP access on, then test again in Outlook.
Can 365 Techies fix 0x800ccc90 for me remotely?
Yes — it's a fast fix for us. We connect securely with Splashtop SOS (you watch the session, we phone you first, and access ends the moment we finish), sort your username, password and POP settings, and get mail downloading again the same day. Call 01202 775566.
Still getting 0x800ccc90?
We'll connect securely, sort your login and POP settings and get mail downloading again — usually within minutes. You watch the whole session, we phone first, and access ends the moment we're done.
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