When your Outlook stops connecting and shows a certificate message, it often points to mismatched settings or expired certificates, and sometimes your PST file gets damaged in the process. This article breaks down what leads to the Outlook Certificate Expired Error and how checking server settings, SSL, and certificates can help. If the PST file itself becomes unreadable, the MSOutlookHelp PST Repair Tool can fix it. It recovers deleted emails, contacts, calendars, and notes from corrupted files and retains metadata like sender, subject, and date. Additionally, it works with password-protected PST files so secured mailboxes are included.