This isn't be sure, but Sourcetree crash may cause .gitconfig breaking, I think.
This is collect settings.
[https]
proxy = http://202.202.202.202:8080
[http]
proxy = http://202.202.202.202:8080
But sometime, it changes to the following.
[https]
proxy = http://202.202.202.202:8080
[http]
As a result of this, I cannot git fetch or git push.
In my company, I have to use https in case via VPN.
It takes time to find out this cause.
Mr. Atlassian, How about investigate about this ?
I use SourceTree version 2.5.5
(I don't use version 3 because of explorer button degradation.)