If a call has the disposition "Agent Error" instead of the right disposition selected by the agent, please note that this happens due to lengthy dispo sessions where the session/connection times out and it registers as "Agent Error".
To change the disposition of the calls, follow the steps:
Go to Contact Center
Contact/Call List
Add Phone Number
Click Filter
On the bottom page, you will find all the details for that particular phone number including the status of the call which can be modified.
Click on the little Blue Pen Icon next to the status
Go to the drop-down menu and change the status with the appropriate one
Click Submit