Push and pull hang to GitHub

[rawnsley]

After working for years, SourceTree suddenly won't pull or push with my GitHub repositories. I can still do both of these from the command line on the same local repository.

I don't have any submodules or subtrees and the operations start but never finish:

I've tried using embedded and system Git from the SourceTree preferences.

I've tried removing and re-adding my GitHub account details using HTTPS and SSH, but it makes no difference.

SourceTree version is 2.7.1.159 and I'm on OSX 10.13.3

[Manju]

Is there an error that it spits out at the end? 

[rawnsley]

It doesn't stop even after several hours. Happy to send any additional logs or run diagnostics if you can give me a steer.