%SPANTREE-2-BLOCK_PVID_LOCAL: Blocking GigabitEthernet1/0/49 on VLAN0101. Inconsistent port type.
In plain English: Spanning tree — the safety system that prevents network loops — detected that this port's VLAN setup contradicts what is arriving on it, and blocked the port to protect the network.
Platform: Cisco IOS / IOS XE. Values shown are the documented defaults — confirm them on your platform with the check commands below.
What it means
Spanning tree — the safety system that prevents network loops — detected that this port's VLAN setup contradicts what is arriving on it, and blocked the port to protect the network. The switch chose a small outage on one port over a loop that could melt down the whole LAN. Traffic over that link for the listed VLANs has stopped.
Likely causes, in order
Native VLAN mismatch on the trunk (one switch tags what the other leaves untagged).
One end of the link is configured as a trunk and the other as an access port.
A VLAN allowed on one end of the trunk but not the other, discovered the hard way.
Check, in order
show interfaces trunkCompare mode, native VLAN, and allowed VLANs on BOTH ends of the link.
show spanning-tree inconsistentportsEvery port spanning tree is currently blocking for consistency reasons, not just this one.
The fix
Make both ends identical: same mode (trunk), same native VLAN, same allowed VLAN list.
After the fix, the port unblocks itself once spanning tree re-checks — confirm with show spanning-tree inconsistentports coming back empty.
Do not 'fix' this by disabling spanning tree protections; the block is the only thing standing between a config slip and a broadcast storm.
Did this fix it for you? One tap — anonymous, nothing to type, and nothing you send is ever published.
Thanks — your tap helps the next engineer. A run of "still broken" reports sends this page back to the top of our re-check list.