Crystal report can't generate report after server restart

Question

I have a Java application deployed in Websphere 9.0 and connects to Crystal report server to generate reports using crystal SDK for Java. Report generation is fine in normal scenario. But when the report server is restarted after a OS patch, report generation fails. Once the app server is restarted or after a duration of 20 minutes of the crystal report server restart, the report generation is fine. The application log shows the web container thread trying to create the enterprise session hangs and couldn't get a session in this case. The report generation is fine through designer in this case. Any settings available to finetune at client side to enable report generation or any other fix can help to solve this issue? Thanks in advance..