Error "Couldn't agree a key exchange algorithm" when trying to log in

When we try to log in to EDI to see if our claims were submitted and to see if there are rejections we keep getting the following error:

Couldn't agree a key exchange algorithm

(see attachment)
How do we solve this?

Thank you

Based on the screenshot, I guess you are using rather old version of WinSCP. Please upgrade to the latest version. If it does not help, please post a session log file.