vSphere client stopped connecting to ESXi 5.5

VSphere client stopped connecting to ESXi 5.5. Error text:

Call "ServiceInstance.RetrieveContent" for object "ServiceInstance" on Server failed.

The request failed because the remote server took too long to respond. (The command has timed out as the remote server is taking too long to respond)

On the day when the client stopped connecting on the hypervisor, nothing was configured. I tried to connect from different computers, first a message about an untrusted certificate appears, then the client tries to connect for a long time, after which the same error occurs everywhere.

The server with the hypervisor is pinged. Did telnet 443. The result is a black command window. lines.

All VMs are running, pinged, and available on ssh, 443, 80, and rdp ports.

NMAP port scan:

Not shown: 989 filtered ports

PORT     STATE  SERVICE

22/tcp   closed ssh

80/tcp   open   http

427/tcp  open   svrloc

443/tcp  open   https

902/tcp  open   iss-realsecure

5988/tcp closed wbem-http

5989/tcp open   wbem-https

8000/tcp open   http-alt

8080/tcp closed http-proxy

8100/tcp open   xprint-server

8300/tcp closed tmi

How can I solve this problem?