The Whonix gateway is running, and the Whonix workstation is losing contact with the Whonix gateway. Therefore, the calculation of the interface parameters in the downstream direction is incorrect.
When changing the IP address for the Whonix gateway (eth0 interface) and (eth1) ProxyVM to a different value. I was able to establish a connection on a Whonix workstation.
My interfaces settings for ProxyVm:
auto lo
iface lo inet loopback
allow-hotplug eth0
iface eth0 inet static
address 10.0.2.15/24
netmask 255.255.255.0
gateway 10.0.2.2
allow-hotplug eth1
iface eth1 inet static
address 10.10.10.10
netmask 255.255.255.0
And for Whonix Gateway these are:
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static
address 10.10.10.11
netmask 255.255.255.0
gateway 10.10.10.10
auto eth1
iface eth1 inet static
address 10.152.152.10
netmask 255.255.192.0
In this configure, I have a stable connection. Can I leave it like that? I also changed NetMask to 255.255.255.0, as @Patrick said it is better to use a different mask to have less leaks.