Some channels and chats on Telegram are marked as pornographic and are blocked by default on the IOS telegram app. You can unblock them in most countries by using telegram web. To do that, go to https://web.telegram.org/a/ on your browser and sign in with your account.
Disable IOS Restrictions 2/5
Then open the settings:
Disable IOS Restrictions 3/5
Scroll down and select "Privacy and Security":
Disable IOS Restrictions 4/5
Lastly scroll all the way to the bottom and check the "Disable filtering" option:
Disable IOS Restrictions 5/5
That should do it! Please mind that it will take a while until the option takes effect on all devices.
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