pycharm git无法使用问题（待解决）

PyCharm 2017.3.1 (Community Edition)
Build #PC-173.3942.36, built on December 14, 2017
JRE: 1.8.0_152-release-1024-b8 amd64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Windows 7 6.1

Git executed successfully Git version is 2.12.2

20:06:39.737: [pyp1] git -c core.quotepath=false -c log.showSignature=false pull --progress --no-stat -v --progress origin master
java.io.IOException: There was a problem while connecting to github.com:22
at com.trilead.ssh2.Connection.connect(Connection.java:817)
at com.trilead.ssh2.Connection.connect(Connection.java:686)
at com.trilead.ssh2.Connection.connect(Connection.java:600)
at org.jetbrains.git4idea.ssh.SSHMain.start(SSHMain.java:173)
at org.jetbrains.git4idea.ssh.SSHMain.main(SSHMain.java:137)
Caused by: java.io.IOException: Key exchange was not finished, connection is closed.
at com.trilead.ssh2.transport.KexManager.getOrWaitForConnectionInfo(KexManager.java:92)
at com.trilead.ssh2.transport.TransportManager.getConnectionInfo(TransportManager.java:231)
at com.trilead.ssh2.Connection.connect(Connection.java:769)
... 4 more
Caused by: java.io.IOException: Cannot negotiate, proposals do not match.
at com.trilead.ssh2.transport.KexManager.handleMessage(KexManager.java:413)
at com.trilead.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:765)
at com.trilead.ssh2.transport.TransportManager$1.run(TransportManager.java:480)
at java.lang.Thread.run(Thread.java:745)
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.