Unable to talk to bitbucket.org. SSL certificate error.

[Levi Danzer]

Sourcetree is no longer able to push/pull/fetch etc... from bitbucket.org. I get the following error.

git -c diff.mnemonicprefix=false -c core.quotepath=false --no-optional-locks fetch origin
fatal: unable to access 'https://bitbucket.org/xxxx/xxxx.git/': SSL certificate problem: unable to get local issuer certificate.
Completed with errors, see above.

I get the same error when trying to clone a repo directly from my Bitbucket account that I have added to Source Tree. 

I have updated sourcetree to the latest version. And am using the embedded git client also fully updated.