title: Gitlab: importing by repo url from old instance to new instance not working
body: <p>I have old self-hosted gitlab instance (Version 8.13.6). Now we've new self hosted gitlab instance (Version 15.2) in different server.</p>
  <p>I need to import projects from the old instance to new instance. For this I am using  &quot;Repository by URL&quot;.  But it doesn't seem to work, whenever I enter project URL from old instance, I also tried to supply valid login credentials for old instance, I get following error -</p>
  <blockquote>
  <p>There is not a valid Git repository at this URL. If your HTTP
  repository is not publicly accessible, verify your credentials.</p>
  </blockquote>
  <p>The project in old instance is not publicly accessible. User needs to login to access the project.</p>
  <p>Is there anyway to import my projects from old instance to the new one?</p>
  <p>Thanks</p>