Preventive maintenance is performed on the equipment, when it was turned on again, the VSS was not established, the configuration was checked and everything is fine.
So the switch "standby" was turned off and the cards were removed leaving only the supervisor card, it was turned on again and the VSS was established.
Does anyone know why this happened?
The information was provided not Enough to tell what was went wrong.
1. First place i will check the log message, when it was not formed VSS, i am sure you get enough logs what went wrong and produces logs.
2. What is the cards you referring that were removed and formed VSS.
3. Are you using any of the Line cards or VSL links ?
4. how is your Access Switches connected to VSS, using L3 or L2 ?
Couple of output to help the community.
show switch virtual
show switch virtual role
sh switch virtual dual-ac su
show switch virtual redundancy
show switch virtual link
Show module switch all
Post the VSS config to understand what interfaces configured.