Jenkins Multibranch Pipeline - /info/refs - command not allowed


I’m trying to set up a build at Jenkins using Git. (I am currently using SVN.)
I use Multibranch Pipeline. After adding the configuration to the repository, it receives the following message:
FATAL: Failed to recompute children of XXX » testing_git
hudson.plugins.git.GitException: Command “git fetch --tags --progress origin +refs/heads/:refs/remotes/origin/” returned status code 128:
stderr: error: The requested URL returned error: 401 Unauthorized while accessing

When I copy the address ( and call it directly in the browser, I receive a message:
The command you’re trying to execute is not allowed.

In /var/opt/gitlab/git-data/repositories/git/pos_test.git/info there was no refs file.
I use command ‘git update-server-info’ - The file has been created. But the message remained unchanged.

What is wrong? Anyone can help?