I guess there is Apex trigger/Class in place on Task object that is validating data,You could grab the error message & reach out to your developer to debug it.
To find the Apex trigger:-
Go--Setup--Customize--Cases--Trigger---Search for a trigger with the name.
Also, If the error is inconsistent then it might be due to the data which you are entering. Based on the data you are entering it might be checking some validations or triggers and firing the error message inconsistently.
The error is due to the trigger on task object, which is calling the class "StampLastActivityHandler" on after insert event. You can check "StampLastActivityHandler" Class for more debugging.
Sorry for this issue you are facing.
I guess there is Apex trigger/Class in place on Task object that is validating data,You could grab the error message & reach out to your developer to debug it.
To find the Apex trigger:-
Go--Setup--Customize--Cases--Trigger---Search for a trigger with the name.
Also, If the error is inconsistent then it might be due to the data which you are entering. Based on the data you are entering it might be checking some validations or triggers and firing the error message inconsistently.
Thanks,
Nagendra
The error is due to the trigger on task object, which is calling the class "StampLastActivityHandler" on after insert event.
You can check "StampLastActivityHandler" Class for more debugging.