Image building error:502: b'GitLab is not responding'

The image building process is failed with the error 502: b’GitLab is not responding’
Why is that happen?
And does the image building failed submission counts for the two submissions per week limit?

OK, finally I got the error message. The error is happened when pip install opencv-python. opencv is required by minerl, so is there anybody installed the opencv-python through requirements.txt correctly?