Hi @Stfkcor ,

This is commonly caused by communication issues between ESXi host and NTP server. If you have a another NTP  server, I would suggest pointing to that and check if issue persists.

To perform some basic troubleshooting from ESXi, please refer --> Troubleshooting NTP on ESX and ESXi 

If using a domain controller as NTP, ensure it NTP mode is configured on it --> https://kb.vmware.com/s/article/1035833 

Hope that helps