This question is a bit outdated, but I ran into the same problem and ended up getting a job for myself, so I thought I was offering something that worked for me here.
When you clone, make sure you are not using the http URL.
Do it:
git clone git@github.com :foo/project-name.git
Not this:
git clone http:
I originally cloned an http URL that did not allow my ssh credentials to be affected. I'm not sure if this is your problem as you said it works the day before, but it might give you something to try.
FYI - to get the url of the current repo you checked, do the following:
cd $REPO_DIR git config --list | grep remote.origin.url
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