%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on FastEthernet0/24 (2), with Switch GigabitEthernet0/2 (1).
I am getting this error , Could anyone help me why I am getting this ?

could you please share the topology??

you ma have configured different native vlans on your trunk interface on both swithces.

Please note by default native vlan is VLAN1 for carrying untagged traffic.

You can check through show interface trunk , which will show you your native vlans configured. To solve this issue you have to configure same native vlan on both end of the trunk link.