Team Services | TFS 2017 Update 1
Import an existing Git repo from GitHub, BitBucket, GitLab, or other location into a new or empty existing repo in your Team Project.
Import into a new repo
From the repo drop-down, select Import repository.
If the source repo is publicly available, just enter the clone URL of the source repository and a name for your new Git repository.
If the source repository is private but can be accessed using basic authentication (username-password, personal access token, etc.), select Requires authorization and enter the your credentials.
Import into an existing empty repo
On the Files page of the empty Git repository, select Import repository and enter the clone URL. You will need to provide credentials if the source repository requires authentication.
Although most of the time the import is successful, certain conditions can cause problems.
Source repository is behind two-factor authentication
The import service uses REST APIs to validate and trigger import and cannot work directly with repositories that require two-factor authentication. Most Git hosting providers like GitHub and Team Services support personal tokens which can be supplied to the import service.
Source repository does not support multi_ack
The import service uses the multi_ack capability of the Git protocol during the import. If the source repository does not provide this capability, the import service can fail to import from the given source. This failure can happen when creating import request or while import is in progress.
Importing from a previous version of Team Foundation Server
If the source Git repository is in a TFS version earlier than TFS 2017 RTM, then import will fail. This happens because of a contract mismatch between latest TFS/Team Services and pre-2017 RTM versions of TFS.
MSA based credentials will not work
Import service relies on basic authentication to communicate with the source repository.If the username / password you are using are not basic auth then authentication will fail and import will fail. One way to check if the username / password you are using are basic auth or not is to try using git.exe to clone your repository using the below format
`git clone https://<<username>>:<<password>>@<<remaining clone Url>>`