Unable to push or pull to github using sourcetree

[JL]

Whenever I click on the icon to pull/push to my git remote repo using sourcetree, I get stuck at the loading process. When I click on the "Show Full Output" tab, I see this message being printed out:

git -c diff.mnemonicprefix=false -c core.quotepath=false --no-optional-locks push -v --tags origin <branch_name>:<branch_name>
Pushing to <repo_ssh_url>
The server's host key is not cached. You have no guarantee
that the server is the computer you think it is.
The server's <remote_repo_ssh_id> key fingerprint is:
<ssh_key_fingerprint_id>
If you trust this host, enter "y" to add the key to


Any idea how I can bypass this, or do I always have to open the terminal and enter the git commands in order to enter 'yes'?

Just to clarify, I'm using a windows machine to run sourcetree and am connecting to github enterprise via ssh.