PC connected to Phone which is connected to 2960 access switch.
When PC disconnected from Phone but switch still learn mac address of that PC from that port and when we connect new PC to that port it is giving switch port security voilation as threshold of maximum mac address set for that access
port is crossed.
Are you using the
switchport port-security mac-address sticky commands
Have a read at this section of the config guide:-
As Alex said could you please check if you are by any chance using the mac address sticky.
Second whats the max address allowed been configured on this port?