@DREEMus 

Hi, have you tested if there is a loop in your network?

Actually how long did you use this switch, maybe a hardware issue?

You can use 2 PC to connect to the issue ports and ping each other when this issue occurs, check if it can ping through.

Hi @Virgo 

have you tested if there is a loop in your network?

This switch is working as last switch, on each port we have customer port (in flat), so there is no option to make a loop. Customer which call us turn off router from power, after 4 days they back and discover issue.

Actually how long did you use this switch, maybe a hardware issue?

Around 2 years, 1 issue occurs around 1.5y ago, 2nd yesterday.

You can use 2 PC to connect to the issue ports and ping each other when this issue occurs, check if it can ping through.

I done this during issue, link/port was UP, but no traffic, zero packets.

  @DREEMus 

Uhmm.......then contacting to support team for a replacement is a good choice, the switch may have been broken.