Can someone explain why I'm getting this error using the Slot tool

Can someone explain why I'm getting this error using the Slot tool error slot In this video I will show you how to solve Unable to Find Slot Error at the time of Digital error_ draggable element must have an item slot Learn how to troubleshoot replication slot errors

error_ draggable element must have an item slot PPDS rescheduling error No slot available for Activity order 0060 G for above, we tried using rescheduling function in CDPSB0 but keep

error slot The prepended slot, the appended slot, the default slot, and messages These You can determine error messages count to show using error-count property  This is a first attempt to work with signal slot AFTER I reinstalled my Qt Creator Since I am adding a slot in I do not get why