We have this issue at two separate client locations:
When connecting to a file on the server (either via "recent" or via "My Apps", the connection fails with the following error: "The file "****" could not be opened. Either the host is not available, or the file is not available on that host"
When connecting to that host via "Local Hosts": you can see the host, but the connection fails.
Solution: add the host to your favorite hosts with the IP-number of the server, then you can connect again.
As this happens with both server 18.104.22.168 and 22.214.171.124, I assume this is a Client Bug.
Client: FM 17.0.3 Windows 10
Server: MacMini, FMS 126.96.36.199 Mac OS 10.13.6 and MacMini, FMS 188.8.131.52 Mac OS 10.14.2
Philip Van Landuyt