Error: "503-OK" when accessing VAMI and vCenter

Products

• VMware vCenter Server

Issue/Introduction

• Trying to login to vCenter and VAMI gives 503-OK message displayed 
• SSH is not available and it hangs when trying to login
• 
• Checking on ESXi Host Client it is visible memory is almost 100% 
• 

Environment

• VMware vSphere ESXi 8.X
• VMware vCenter server 8.X

Cause

• ESXi hosts do not have enough memory

Resolution

• Add more ESXi hosts for cluster in order for VMs be able to migrate and for the memory to not be overused 
• Workaround:
  • Stop some VMs in your environment to get access to the vCenter server