After a tenant-to-tenant migration in Microsoft 365, Outlook may repeatedly prompt you for your password even though you have already entered the correct credentials. This happens because Outlook caches the old authentication tokens and server endpoints from the previous tenant. The cached data conflicts with the new tenant configuration, causing authentication loops. This article explains … Read more
After changing your Microsoft 365 password, Outlook may refuse to add your account again. The error often appears as a repeated password prompt or a message that Outlook cannot connect to the server. This happens because Outlook caches old credentials in Windows Credential Manager and in the registry. This article explains why the cached data … Read more
You double-click an attachment in Outlook, it downloads to your computer, but then nothing opens. Or you see an error message saying Windows cannot open the file. This problem happens when the file association for the attachment type is missing or broken on your Windows system. It can also occur if Outlook is running in … Read more
You click an attached Word document or Excel spreadsheet in Outlook, but the preview pane shows a blank area, an error message, or the message “This file cannot be previewed.” This happens even though the file opens correctly when you double-click it. The root cause is usually a broken or disabled preview handler in Windows, … Read more
Error 0x8004010F appears when Outlook cannot locate or connect to the mail server while sending messages through Office 365. This error typically occurs because Outlook has a corrupted or outdated Autodiscover cache, an incorrect mail profile, or a damaged offline data file. This article explains the root cause of error 0x8004010F and provides step-by-step fixes … Read more
When you try to send an email in Outlook, you may see error 0x800CCC0E along with the message “Connection to the server was refused.” This error means Outlook cannot establish a connection to your outgoing mail server, also known as the SMTP server. The problem is almost always caused by incorrect account settings, a firewall … Read more
Outlook error 0x800CCC0F appears when you try to send an email and the connection to your mail server is lost. This error means Outlook started talking to the outgoing SMTP server but the server ended the session before Outlook could finish sending. The problem is almost always on your side — a misconfigured outgoing server … Read more
Outlook error 0x8004060C appears when a message in the Outbox cannot be sent and blocks the outbound mail queue. This error is caused by a corrupted outgoing message, often due to a large attachment, a damaged email draft, or a conflict with an add-in. This article explains why the error occurs and provides step-by-step recovery … Read more
Outlook error 0x80042108 appears when you try to send or receive email and the operation fails before completing. This error means Outlook cannot connect to your incoming or outgoing mail server within the allowed time. The cause is almost always a network timeout, an incorrect server port, or a security software block. This article explains … Read more
When you try to send an email to a recipient from the Outlook Address Book, you may see error 0x80048002. This error prevents Outlook from reading the Address Book container and stops you from selecting contacts. The problem occurs because the local copy of the Address Book is outdated or corrupted. This article explains why … Read more