Issues with CISCO-JPC-40GBASE-CR4 stack cables

[Nadia88]

Hello everyone,
I need your help with a problem with meraki stacks (MS225-48FP), occasionally a stack switch goes down but for no reason, on some forums I read that there are known problems related to CISCO-JPC - 40GBASE-CR4 stack cables, do you have any information about this?

[PhilipDAth]

Are you using one of the Meraki part numbers:
MA-CBL-40G-50CM
MA-CBL-40G-1M
MA-CBL-40G-3M

I haven't had any issues with these.

[Nadia88]

Hi Philip, 
We use this model MA-CBL-40G-50CM and on the switches we see this logg related to the stack port:

port: 53, old: down, new: 20Gfdx
port: 53, old: 20Gfdx, new: down

[GIdenJoe]

You may have a bad cable or the QSFP is not seated 100% inside the slot.
Maybe try switching around your cables and see if the problem follows the cable or not.

The speed should also be 40 Gbps.

[PhilipDAth]

I would try reseating as @GIdenJoe has said, and if that doesn't work, contact support.  You might have a faulty component.