Catalyst 3850 stack issue

[Anukalp S]

Hello.. currently I have been running into an issue where my 3850 switches giving error of one stack port down, I have tried replacing stack cable but still same issue. I have been running ver.03.07.04E. Please help.

SwitchCS1#sh switch
Switch/Stack Mac Address : 40a6.e81e.1b80 - Local Mac Addr

Switch#   Role    Mac Address     Priority Version  State 
------------------------------------------------------------
*1       Active   40a6.e81e.1b80     2      V04     Ready               
 2       Standby  94d4.6984.8680     1      V07     Ready               

Switch#   Role    Mac Address     Priority Version  State 
------------------------------------------------------------
*1       Active   40a6.e81e.1b80     2      V04     Ready               
 2       Standby  94d4.6984.8680     1      V07     Ready               

Switch#sh switch stack-po

Switch#   Port1     Port2     
----------------------------
1         DOWN      OK        
2         OK        DOWN    

 Switch#sh switch stack-port summ

 Port Status  Neighbor  Cable Length   Link OK   Link Active   Sync OK   #Changes to LinkOK  In Loopback   
-------------------------------------------------------------------------------------------------------------------
1/1        DOWN         NONE      50cm           Yes       No            Yes       9                   No            
1/2        OK           2         50cm           Yes       Yes           Yes       1                   No            
2/1        OK           1         50cm           Yes       Yes           Yes       1                   No            
2/2        DOWN         NONE      50cm           Yes       No            Yes       4                   No           

[nazimkha]

If Stack port is down, usually it is the stack cable or stack port. Try to change the combinations to find out which one is bad.
Ensure that the stack cable is fitted in correct direction

[balaji.bandi]

If you have tried replacing the Stack cable and reloaded the switch, you have still issue.

03.07.04E - worth looking some bugs against reports.

We have same issue with different version, after moved to latest version it was solved. (not necessarily this is an issue with your case)

if not found any bugs open a TAC Case.