There could be a number of reasons that a call cannot be ended. Here are the most likely reasons why a visit cannot be ended.
Have all the activities for the visits been completed? All activities must be completed before the visit can be ended.
Has the carer had another visit with the service user that has not been ended? If there is an outstanding visit for the same carer and service user, you won't be able to log out of the current visit. You may need to adjust your tenant preferences to allow the old visit to be completed.
Is the carer in the correct group and role? If they are in the incorrect group or role, they won't have the proper permissions for the visit.
Is the time setting in tenant preferences correct? 'How Long Before The Planned End Time Can A Visit Be Ended?' If this is set to 15 minutes and they are now over this time, they won't be able to end the visit.