Why is my perforce server refusing connections?

[GerishSonya]

For over a year, I successfully ran Perforce development servers for a small group of users without any issues. However, last week, the users reported that their clients were unable to connect. To investigate, I logged into the server and attempted to run the command "p4 info," but encountered the following Perforce client error:


Connect to server failed; check $P4PORT.

connect: 127.0.0.1:1666: Connection refused
Additionally, when I tried running "p4 -p servername:port," I received a similar response indicating a connection refusal, even when using the server's IP address.

What could be the cause of this sudden connection refusal, and how can I troubleshoot and resolve this issue to restore connectivity for the users? Any insights or suggestions would be greatly appreciated.