%PM-4-ERR_DISABLE: loopback error detected on Fa0/14, putting Fa0/14 in err-disable state

[Ayush Srinet]

%PM-4-ERR_DISABLE: loopback error detected on Fa0/14, putting Fa0/14 in err-disable state, what is best reason in

ME-3400-24TS-A.

[Abzal]

Hi,

It means there is L2 loop that spanning-tree detected.

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00806cd87b.shtml#topicsubsub1

Check you network topology and f0/14 interface configuration:

sh run int f0/14

What device is connected to that port?

Hope it will help.

Best regards,
Abzal

[Peter Paluch]

Hello Abzal,

It means there is L2 loop that spanning-tree detected

Indeed, there is a switching loop - but the message indicates that the port was not disabled by STP but rather by the port receiving its own LOOP frames. This self-looped detection is distinct and separate from STP. See for more info here:

https://supportforums.cisco.com/thread/2001389

Best regards,

Peter