Dell Networking N3048 with cisco switch

Hello,

I have Dell Networking N3048,  switch:

with one access port

i

interface Gi1/0/6
description "Vxxxxx"
switchport access vlan 12
exit

on other side are Cisco 2960, also with access port.

Mar 22 07:10:06: %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk FastEthernet3 VLAN2.
*Mar 22 07:10:06: %SPANTREE-7-BLOCK_PORT_TYPE: Blocking FastEthernet3 on VLAN2. Inconsistent port type.PVST+: restarted the forward delay timer for FastEthernet3

what is the problem ? how i fix ?

regard

gadi

Cisco blocks this port, because received tagged packets: