I have found warning at DB server when user has reported Application dis-connectivity.
1) User reported Application Dis-connectivity Error as attached.
2) We investigate the issue and look in to the Event logs and found below WARNING. Event Id : 4227
TCP/IP failed to establish an outgoing connection because the selected local endpoint was recently used to connect to the same remote endpoint. This error typically occurs when outgoing connections are opened and closed at a high rate, causing all available local ports to be used and forcing TCP/IP to reuse a local port for an outgoing connection. To minimize the risk of data corruption, the TCP/IP standard requires a minimum time period to elapse between successive connections from a given local endpoint to a given remote endpoint.
Please confirm will user application error is due to this above error.