Reverting Merge Commit fails

Steps I followed

created a new branch
make a change to the file from the original commit in the new branch
create a pull request
merge the pull request
click the merge commit id
click on operations, revert
select the main branch in the pop up
select create a new branch for this commit and start a pull request on the revert page that shows up
click propose file change

I get an error
Unable to apply patch 'Error: Stdout: Stderr: error: No valid patches in input (allow with "--allow-empty") Err: exit status 128'

The ‘new patch’ textfield just
shows
revert b8a3fce70c7ea5f58d692abcfc60f10b06344250

instead of the code to be changed

I am using gitea 1.21.4 version running on windows server 2022.

Please can you tell me what is the issue that’s causing this?