CI: encountered end of file

Several days ago my pipelines/jobs started to fail cause of the following error. I made no changes to .gitlab-ci.yml or repository settings.

Using Shell executor...
Running on ...
Cloning repository...
Cloning into '/home/gitlab-runner/builds/cd30373a/0/Wt4/repositoryname'...
fatal: unable to access 'https://gitlab-ci-token:xxxxxxxxxxxxxxxxxxxx@gitlab.com/Wt4/repositoryname.git/': Encountered end of file
ERROR: Job failed: exit status 1

What additional info should I provide to receive an answer?

Thanks in advance!