@AlaudeenP16618784 This message usually means that you've encountered an error entering data. For example, if you were to manually (without Pega running) try to enter data into a field that didn't accept all of the data you were entering, the screen would "lock" and require you to click the "Escape" key before you could enter any other data to the screen. You might be trying to send something like five characters to a field that only accepts three. You might also have your field location "off" from the actual location of where the data goes. You can check this in interrogation by manually entering the data and then checking the value of the field. It might just be defined outside of the bounds of where data can be entered. I don't believe this is related to running multiple sessions unless you have both sessions defined with the same short session name.