if you get a message like:
Received message too long
when sftping to your server , check .bashrc , script on the server you are trying to connect , if there is a type-to-output part like an echo command somewhere.
I had done this thing to check if .bashrc
was executed (added echo "welcome.." ) and I had this problem with sftp.
After removing the echo line from .bashrc , I was able to connect again with sftp.