Getting fatal error when trying to clone from Bitbucket into SourceTree

[Ron Rabakukk]

I am trying to clone a repository in Bitbucket to my local PC using SourceTree. I have added my SSH key to Bitbucket and set up my private key in SourceTree, and on the remote tab I see the list of available repositories. I click on the clone link next to one of the repositories and it fails, giving this error:

Command: git -c diff.mnemonicprefix=false -c core.quotepath=false --no-optional-locks ls-remote https://ronrabakukk@bitbucket.org/pmas-de/hscs-kpi-1a.git
Output:
Error: fatal: unable to access 'https://bitbucket.org/pmas-de/hscs-kpi-1a.git/': SSL certificate problem: self signed certificate in certificate chain

I am using the same SSH key pair on another PC and they work fine. Any idea why it is failing?