我无法让Jenkins通过SSH在BitBucket上克隆git存储库。出现以下消息失败：

Building in workspace /var/lib/jenkins/workspace/test
[ssh-agent] Using credentials git (git@bitbucket.org:<user>/<repo>.git)
[ssh-agent] Looking for ssh-agent implementation...
[ssh-agent]   Java/JNR ssh-agent
[ssh-agent] Started.
Checkout:test / /var/lib/jenkins/workspace/test - hudson.remoting.LocalChannel@2b619bca
Using strategy: Default
Fetching changes from 1 remote Git repository
Fetching upstream changes from origin
ERROR: Problem fetching from origin / origin - could be unavailable. Continuing anyway
hudson.plugins.git.GitException: Command "git fetch -t origin +refs/heads/*:refs/remotes/origin/*" returned status code 128:
stdout: 
stderr: ssh: connect to host bitbucket.org port 22: Connection refused
fatal: The remote end hung up unexpectedly

采取的步骤

• 创建一个SSH密钥对
• 将公共密钥添加为BitBucket上存储库的部署密钥
• 在Jenkins Credentials Manager插件中安装SSH密钥和用户名（尝试过’git’和我的BB帐户名）
• 尝试使用URL的形式在构建中克隆存储库

git@bitbucket.org:<user>/<repo>.git

我也尝试过不使用凭据管理器并手动将密钥安装在中/var/log/jenkins/.ssh/，但无济于事。

有什么想法我做错了吗？