Why can't I "save" when adding an account?

[Solo Gao]

Hi guys,

I am trying to use SourceTree MAC to connect to the gitlab server of our group. We are using SSH to authenticate. In Sourcetree-Preferences-Accounts, I tried to set the Host as the Gitlab Enterprise and Gitlab CE, set the url as "https://gitlab.thewebsitename.com/", enter the username and enter the token as the password. SourceTree is able to recognize my SSH Key. However, nothing happens after clicking "Save" for about 100 times. I am able to add a bitbucket account. So how can I solve that problem? Thanks.

BTW, I tried the Sourcetree 4.0.2 and 3.2.1, but found no success.