Hi @Thành Tiến Trương,
I'm glad your problem was solved, and I learned a lot from your solution. Thank you for sharing your sparkling ideas!
Now I'll summarize this problem of user in AD group not being able to login to SharePoint.
Troubleshooting is as follows:
- Check if the group is added to Deny access via network.
- Check if the group have permission to SharePoint. (Settings > Site settings > Site permissions > Check Permissions)
- Remove group permissions and re-add permissions.
- Clear the browser cache and try again to access the SharePoint Site.
Please click "Accept Answer" and kindly upvote it, as it will help others who are facing the same problem as you. Thank you for your understanding and cooperation!
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