Can’t access our chat? Do this:
Go to the web version of Telegram. This solution will NOT work using the app version. Use this link: https://web.telegram.org/a/
Once you get there and login, go to Settings, then Privacy and Security. Go to the section that says Sensitive Content and check the box that says Disable Filtering. This box must be checked.
Restart the phone and go back into the app on your phone. You should be able to enter the group.