If new Salesforce users have email accounts hosted on Microsoft Office 365 with Safe Links protection enabled, the "Verify Account" URL in new user welcome emails will be automatically rewritten by Microsoft's security scanning service.
When Microsoft Office 365 Safe Links scans an outbound email, it rewrites all URLs for security inspection purposes. Because the Verify Account URL is a one-time-use link, Microsoft's scan consumes it before the email reaches the user's mailbox. The link expires immediately, so when the user clicks it, they are redirected to the standard Salesforce login page — sometimes with an invalid username/password error — instead of the "Change your password" page.
The only resolution is to add the Salesforce domain to the Safe Links Allow List (also called the "Do not rewrite the following URLs" list) in Microsoft Defender for Office 365.
Before following the instructions below:
safelinks.protection.outlook.com URL.For more details on Safe Links policy configuration, see Set up Safe Links policies in Microsoft Defender for Office 365.
Set up Safe Links policies in Microsoft Defender for Office 365
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