What does it mean? What do I do about it?
This refers to connections per "remote server" (connection pooling).
For small systems, 5 is the suggested starting value. Larger systems may wish to balance very large numbers of remote servers vs the number of connections per server.
For a deep dive on remote connection-related client startup parameters, see this Progress KBase article on How to set the values for the startup parameters -Ma, -Mn and -n