Using classic Outlook for Windows in business environments
Hi @TIM LEWIS
Thank you for sharing your concern.
Based on your description, looks like your current Outlook Classic is experiencing both a synchronization and an authentication issue. Since you’re receiving spam emails but not regular emails, this usually indicates that your Inbox is not syncing properly. At the same time, the repeated login pop-up and your password not being accepted suggest there may be an authentication issue with your account (for example, outdated/corrupted saved credentials, or a mismatch between your current password and what Outlook has stored).
To troubleshoot this, you could follow these steps:
Confirm your password works by logging in via Outlook Web App
Access your account on OWA using your password to verify it works normally. If you can log in successfully, the issue is likely isolated to the Outlook desktop app. If not, please reset your password and try again.
Additionally, check whether you are receiving emails normally in your Inbox via OWA. If you are not receiving emails on OWA either, check if any rules are automatically moving emails to Junk, Deleted Items, or another folder.
Also review Mail > Junk email settings to ensure legitimate senders are not blocked.
Clear any saved credentials and re-enter your login
If you recently changed your password or your current password is not working properly in Outlook Classic, you can try to clear and re-enter your credentials:
Close Outlook completely.
Go to Control Panel > Credential Manager > Windows Credentials.
Remove any entries related to Outlook, Office, or MicrosoftOffice/ADAL.
Reopen Outlook and sign in again when prompted.
Recreate your Outlook profile
If the above steps do not help, you could consider recreating your Outlook profile:
Close Outlook. Go to Control Panel > Mail > Show Profiles.
Click Add and create a new profile.
Re-add your email account. Set the new profile as default, then open Outlook and check if the issue persists.
Reference:
Create an Outlook profile - Microsoft Support
I hope this helps.
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