After changing the IP Address of a Domino server, a Notes client is unable to connect; "Server Not Responding" errors display.
By clicking a Notes application icon on Notes workspace to access to the application(database), it caused the above connection error.
Then, when the customer used "Trace Connections" (Notes Preferences -> Notes Ports -> Trace), first it failed to connect to Domino server, because it used the old IP address.
However, it continued connection attempt and used host name of Domino server, and it successfully connected to Domino server.
After that, by clicking a Notes application icon, Notes could connect to the application(database).
He wants "by clicking a Notes application icon" to work as "Trace Connections", and continue connection attempt by changing the value, IP address, host name and server name.
Reference:
"Unable to connect to Domino server from a Notes client after changing the server's IP address"
https://support.hcltechsw.com/csm?id=kb_article&sysparm_article=KB0037352
Much needed. The same issue occurs after switching on or off a VPN connection. With VPN on, server X can be addressed directly via its host name, which gets cached by the Notes client. After disconnecting from VPN, the client takes ages to realize that it should now connect to the same server via pass-through, although the correct pass-through connection is present in the address book.