CI unable to clone with HTTP 502

Gitlab CI is unable to clone the repository. The request to /user/repo.git/ results in an instantaneous HTTP 502 response.

fatal: unable to access 'https://gitlab-ci-token:79a4891ca47844fb84069e004862d1@git.foo.bar/user/repo.git/': The requested URL returned error: 502

Directly accessing https://git.foo.bar/user/repo.git/ also results in a HTTP 502.

The new location block

location ~ [-\/\w\.]+\.git\/ {

was installed.