I'm having Incompatible issues while testing the existing bot

This Issue has been resolved by configuring the General Information > Robot pool > add robot pool which contain Current Active Agent (Robot).

Remember While creating a  Robotic Task (BOT) add Robot pool which contains Current Active Agent (Robot)

can you please elaborate the steps you used to achieve this?

We can't directly assign Tasks to a Robot . You need to create Robotic Pool First and You can call that  in General information Tab  or at the time of creation. 

If you want to run your Robotic Task the following conditions needs to be met..

1.   Robot needs to be up and running   https://docs.appian.com/suite/help/21.1/rpa-8.9/components/robots.html
2. Your Task must be assigned to robot (Robotic Pool comes into picture here)  
3. Mandatory Permission Tags needs to be defined to Task  and robot viceversa  https://docs.appian.com/suite/help/21.1/rpa-8.9/components/security.html#assign-or-edit-permissions

We can't directly assign Tasks to a Robot . You need to create Robotic Pool First and You can call that  in General information Tab  or at the time of creation. 

If you want to run your Robotic Task the following conditions needs to be met..

1.   Robot needs to be up and running   https://docs.appian.com/suite/help/21.1/rpa-8.9/components/robots.html
2. Your Task must be assigned to robot (Robotic Pool comes into picture here)  
3. Mandatory Permission Tags needs to be defined to Task  and robot viceversa  https://docs.appian.com/suite/help/21.1/rpa-8.9/components/security.html#assign-or-edit-permissions