If I were you, I would check firmware and driver versions.
In case of need, they should be updated. Do not ignore also BIOS Version.
Check if your ESXi uses latest build version.
Will you be able to provide also more details?
Your post needs moving to the correct area for ESXi, so I have reported it to the moderators.
@memoscoso nope, I have not found any solution yet, I just updated the Cisco server firmware, and still happening. I am exploring on updating the driver, see if it helps. Mine is ESXI 6.7 which will be unsupported very soon.
I just wanted to mention - that the firmware update is good but the driver update is even better.
I am expecting that after the driver updates - should be ok.
One more thing I forgot to add - please check in iLO, iDrac - but only from CIsco - I don't know how it calls on Cisco servers - if the network card itself is ok. Maybe port flapping sometimes. I mean maybe in Logs you will find something like port up / port down.
Both Cisco Firmware and VMware updated to latest version or at least last supported version for ESXI 6.7
The issue persists.
I check the Cisco IMC, the network card is working fine, need to drill down to log file.