Importing from GitLab, failing to import.

I was trying to import a repo from GitLab to GitHub. Suddenly it failed and I got an Error email.
So My repo on GitLab has around 14000 files and 9.7GB in size. Note that each file is less than 10MB.

Why is happening and what should I do. There was no more information.

P.s.: The importing process goas to the end but then I got the error.