But are you able to receive any AS2/MDN’s from your TP during this error times?? looks like this is a network issue based on your NetException.
“Earlier it was working fine,but since 3 to 4 days,I am getting the following error:”-- are you sure that no recent changes have been done in your network communication layer or wM AS2 comm transport side??
Please also make sure if your TP AS2 server is accessible when the time this error occurred or you may check with your sysadmins whether they have any communication monitoring in place to check whether there is any connection/router issues when reaching the external AS2 service