Hey
have you tried regenerating the ssh keys on the ASR and run a debug ip scp when your trying to do it , also try outbound to the sftp server see what it produces , basically try re-apply the ssh to the ASR and make sure there's connectivity between the server and router
another thing to try is use putty just to see if it faces the same issue , if it works it may be an issue on solarwinds side , if that's not working either prob the router as unlikely issues with 2 different apps at the same time
just some options sure let me know if you get anywhere and if not provide the debugs if possible
