If you get the following message on any channel/chat, follow these steps to unblock it.
Using the web version of Telegram on your phone.
- Search on google for Telegram Web.(https://web.telegram.org/)
- Login. You will receive a code on Telegram app. Put the code and continue.
- Once you're in,click the 3 dots on the upper left and go to settings.
- Go to "Privacy and Security"
- Scroll down and make sure the blue check is on for "Disable Filtering"
- Restart Telegram App.