Terminal session : Command issue


I am trying to connect to terminal session( IBM EHLLAPI), for Micro Focus Rumba. The session is created, connection is happening, but some times it is entering the command and sometimes it is not. When it is not able to enter the command , it is displaying the following error message:
“Terminal Session : There was an error connecting to terminal. Error code:Error”

Could you please suggest what will be the issue.

Thanks & Regards,