Fix Office 365 Login Problems on Windows & Web (2025 Guide)
If your Office 365 login keeps failing, showing a blank screen, or getting stuck on “signing in,” don’t worry — this is one of the most common Microsoft 365 issues users face in 2025. The problem usually occurs due to authentication token mismatches, cached credentials, or browser session conflicts. In this guide, we’ll walk you through every step to fix Office 365 login problems on both Windows and the web version.
🔍 Understanding Office 365 Login Issues
Office 365 uses Microsoft’s cloud-based identity system for authentication. Even a minor error — like outdated cached data or an expired token — can trigger endless sign-in loops or unexpected errors like:
- “Something went wrong. [AADSTS50058: User session not found.]”
- “Your account or password is incorrect.”
- “Sign-in required repeatedly in Office apps.”
These errors usually appear when the system can’t verify your credentials securely. Let’s fix that step by step.
⚙️ Step-by-Step Fix for Office 365 Login Problems
1️⃣ Clear Cached Credentials
Old credentials are the number one cause of Microsoft 365 login loops. To clear them:
- Open Control Panel → Credential Manager → Windows Credentials.
- Find and remove all entries containing “MicrosoftOffice16,” “Outlook,” or “ADAL.”
- Restart your computer and log in again.
This resets your authentication cache and forces a fresh token request.
2️⃣ Reset Browser Cookies & Cache
If you’re using Office.com or Outlook Web Access (OWA), clear your browser’s cache and cookies. Then reopen Office.com in an incognito/private window. This bypasses any stored session tokens that cause repeated sign-in prompts.
3️⃣ Check System Date, Time & Region
Incorrect system time can break your connection to Microsoft’s authentication servers. Always enable Set time automatically and select the correct region in your Windows settings. If your clock is even a few minutes off, login may fail.
4️⃣ Update & Repair Microsoft 365 Apps
Open Control Panel → Programs → Microsoft 365 → Change → Quick Repair. If that doesn’t help, choose Online Repair (requires internet). This reinstalls missing authentication components and sync services.
5️⃣ Check for Conflicting Accounts
Many users have both personal Microsoft accounts (e.g., Outlook.com) and work/school Office 365 accounts. If both are signed in simultaneously, the system can confuse the authentication path. Log out of all accounts and sign in with only one — preferably the one with your Office 365 subscription.
6️⃣ Disable Modern Authentication (Temporary Step)
If your admin enabled Modern Authentication (MFA), try disabling it temporarily via Azure Active Directory → Properties. Then re-enable it after successfully signing in. Alternatively, generate an app-specific password if using Outlook 2016 or older.
💡 Extra Tips for Reliable Login
- Use portal.office.com instead of outdated URLs.
- Keep Windows updated — many login bugs are fixed through cumulative updates.
- If using corporate credentials, verify with your IT admin that your account license is active.
📲 Fix Office 365 Login Issues on Mobile
If you can’t sign in on your phone’s Outlook or Teams app:
- Go to Settings → Accounts → Remove the Microsoft 365 account.
- Clear app data and cache.
- Re-add your account with your organization’s domain (example@yourcompany.com).
For iPhone users, reinstalling Outlook or updating to the latest iOS often resolves stuck sign-in loops instantly.
🔐 Advanced Troubleshooting (Admin Tips)
Admins can fix persistent login issues by running these PowerShell commands:
Get-Module -ListAvailable MSOnline Connect-MsolService Set-MsolUser -UserPrincipalName user@domain.com -StrongAuthenticationRequirements @()
This resets MFA settings for the user and resolves authentication conflicts on multi-device setups.
📞 Need Help Fixing Your Office 365 Login?
If login issues are still persisting, our experts can assist you live via WhatsApp. We’ll walk you through step-by-step solutions for Office, Outlook, or Teams sign-in errors.
💬 Chat on WhatsApp for Instant Help