Evidently you cannot just scp files from an old Solaris box when you’re on a RHEL/CentOS system … there’s an incompatibility between them that requires you to (1) install scp1 on the Solaris server {not likely in a prod environment} or (2) use sftp to transfer the files.

 

Server1: Red Hat Enterprise Linux Server release 7.6 (Maipo)
Server2: Solaris 5.9

lisa@server1:~/$ scp lisa@server2:/data/stuff/file1.txt ./input/
lisa@server2’s password:
scp: warning: Executing scp1.
scp: FATAL: Executing ssh1 in compatibility mode failed (Check that scp1 is in your PATH).