Cannot Sign In to Some Office 365 Portals/Tools

Question

I can no longer sign into certain online Office 365 portals. We are in the process of migrating from Exchange on prem to Office 365 and when I try to start a new migration batch, it says "We couldn't sign you in. Please try again.". But it works to sign into admin.microsoft.com, security.microsoft.com, Outlook, etc. Another portal I can’t sign in to is Teams online, the desktop and mobile application work just fine, only the web app doesn’t let me sign in. We are not blocking third-party cookies either. The address bar flashes a login.microsoft.com url on and off during the sign in process.

Things I've Tried

• Added all office/Microsoft URLs to trusted sites and firewall whitelists
• disabled MFA
• tried on different networks/hotspots
• different computers
• off our domain
• on personal computer
• on mobile devices
• different versions of Windows
• different browsers (Edge, Chrome, and Firefox)
• private browsers
• removed Office licensing and added it back

Answer 1

Hi @SamG-5656 ,

Just wondering if the account you're using is a global admin? We recommend that you appropriately revoke most permissions except for global admin and Teams admin to see if you can successfully sign in.

In addition, there is a similar thread here, where some users say that logging in by modifying the time zone is successful:

Teams-Login-Error :We couldn't sign you in. Please try again. - Microsoft Q&A

Hope this helps!

---

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment". Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread