We are using an on-prem Bitbucket server. Before you can login using a standard authentication of a username and password, your browser must be authenticated using a personal certificate. I can't seem to find any documentation that shows if this even supported. Note that currently we are using Github Desktop to access our repo without a problem. I'd prefer to use Sourcetree since that is what Bitbucket recommends.
Here are snippets of log files I found. Note that I've redacted sensitive information with x's.
2de488d5-ae1c-4885-b17d-8928bedbad93sourcetree.log
2019-04-01T18:43:31: VaultClient::Delete
2019-04-01T18:43:31: credentials not found for git:https://xxxx@xxxxx.xxxxxxx.com
2019-04-01T18:43:31: VaultClient::Delete
2019-04-01T18:43:31: credentials not found for sourcetree-rest:https://xxxx@xxxxx.xxxxx.com
sourcetree.log
ERROR [2019-04-01 18:43:31,014] [1] [SourceTree.Exceptions.RemoteHostException] [Log] - Failed to check login for user [xxxxx]
ERROR [2019-04-01 18:43:31,041] [1] [SourceTree.Exceptions.RemoteHostException] [Log] - Failed to check login for user [xxxxx]
