If you’ve got a firewall like CSF or iptables running that logs to your xen console it is possible that the Xen console will lock your VPS. Also other applications may log data to the console, which can lock up Xen. The only way to unlock your VPS is doing a reboot.
dmesg -n 1
This command prevents that messages will be written to the screen (the Xen console*). If you’re using for example a firewall like CSF it will print by default all iptables blocks to the screen and lock the VPS up. dmesg prevents this for you.
The serial console in SolusVM is the Xen console.