Revert to the Default Theme

1: First, go to Settings by clicking three horizontal lines at the top left corner » Settings.

2: Scroll down until you see "Chat background" and click "Use default color theme"

3: The default theme should now be restored!

See also:

• How do I set a new theme?
• How do I create a new theme?

To contact Telegram support, go to Settings, and scroll down until you see the 'Ask a Question' button at the bottom.

If you want to join us, check out the Telegram Support Initiative.