Travis cannot install Ruby 2.7.2 for osx_image: xcode13.3

I have upgraded ruby versions in the past without problems.
I changed the contents of .ruby-version but this time around I got the following error:

I also tried

- rvm install 2.7.2

The same thing happened

This is relevant data in my .yml file:

language: objective-c
osx_image: xcode13.3

Please help me and thanks in advance!