Cisco SG 350x stacking over the fiber issue

[pouzarpetr04117]

Hello friends,

I need help solve my problem. I have 4 switches (two SG350X-48P and two SG350X-24P, all updated on last firmware version.) and I need join them to the stack. If I use metallic cables on XG1 and XG2 ports, everythings go fine and stack is working. If I use fiber on XG3 and XG4 ports just for the data, it's working too. But if I mark XG3 and XG4 ports like a stacking ports , it stops working. 

Had anybody same issue?

Thanks for any advice.

[balaji.bandi]

what is the firmware version, not that I aware or heard have some kind of issue in the community?

here is the guide GUI

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5408-configure-stack-settings-on-an-sg350x-switch.html

Cli

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350-series-managed-switches/smb5555-configure-stack-settings-on-a-switch-through-the-command-lin.html