Julia package documentation “Load key: invalid format”

I followed the hosting documentation (Documenter.jl) to deploy the documentation for the TSSOS Julia package. But I got the following error in the workflow (GitHub Actions):

Failed to add the RSA host key for IP address ‘’ to the list of known hosts (/home/runner/.ssh/known_hosts).
Load key “/home/runner/work/TSSOS/TSSOS/docs/.documenter”: invalid format
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
┌ Error: Git failed to fetch git@github.com:wangjie212/TSSOS.git
│ This can be caused by a DOCUMENTER_KEY variable that is not correctly set up.
│ Make sure that the environment variable is properly set up as a Base64-encoded string
│ of the SSH private key. You may need to re-generate the keys with DocumenterTools.
└ @ Documenter ~/.julia/packages/Documenter/FuXcO/src/Documenter.jl:554

Any idea to fix this issue? I use the Windows 10 system and the key pair was generated by DocumenterTools.genkeys.