my server is attacked

I'm getting messages for brute force from china
I'm blocking each IP manually but the attacker changes his IP

I installed CSF and tried to block china using CC_DENY in CSF but i'm getting error:

Error: The VPS iptables rule limit (numiptent) is too low to add 6892 rules (1293/4096) - *IPs not added*, at line 5340

now the system load average is 46.88

I don't know what to do...

Hello,

Did you try and contact your VPS provider for a help? They might have ready and free solutions for it.

What service is under an attack?

Manually blocking IP's is useless and a waste of time.
Configure CSF that an IP is Temp blocked after 3 failed attempts.

Use CSF to block the attackers, or follow the instructions at https://help.directadmin.com/item.php?id=380