GitLab, Jenkins, project in folder

GitLab Enterprise Edition 9.1.3-ee e28218c
Jenkins 2.73.2 with GitLab plugin 1.5.1
Jenkins says: “Build when a change is pushed to GitLab. GitLab CI Service URL: https://subdomain.example.com:18443/project/ABCD/gitlab-hook-test
I put that into gitlab, settings, integrations, Jenkins CI. I have ssh key auth set. User/password is set anyways.
Push “Test settings”. Receive: We tried to send a request to the provided URL but an error occurred: execution expired.

What do I do wrong?