One SEP client is not communicating to SEPM console

Hello All,

Good Morning ,

I have one sep client running in the version 12.1.7061.6600, This client is reporting to SEPM cosnole (14.0. Mp). post SEPM cosole upgrade SEPM 14.2.1(14.2.4814.1101). Now client is not communicating to SEPM console . its showing offline in SEPM console. 

We did the all basic steps. if any suggestion for further analysis.

Sep client version  12.1.7061.6600(client is running in windows server 2003)