OVPN connections and drop rules

Hi to all!
Have a little problem. Have a CCR mikrotik and OVPN server on it. It works fine for years, bun yeaterday i have a problem. My clients can’t connect to the server.
First step is to see logs. So i see a couple of attacs to Tik via winbox, SSH, API from some external IP addresses. It was not a problem, because i did’t have an access from internet for all services. But next was s multiple TCP connections from about 10 IP’s via OVPN and it continues:
21:48:33 ovpn,info TCP connection established from 54.251.31.129
21:48:34 ovpn,info TCP connection established from 54.183.255.129
21:48:34 ovpn,info TCP connection established from 54.241.32.97
21:48:37 ovpn,info TCP connection established from 54.248.220.33
21:48:37 ovpn,info TCP connection established from 54.232.40.65
21:48:39 ovpn,info TCP connection established from 54.244.52.193
21:48:42 ovpn,info TCP connection established from 107.23.255.1
21:48:43 ovpn,info TCP connection established from 176.34.159.225
21:48:44 ovpn,info TCP connection established from 54.250.253.225
21:48:46 ovpn,info TCP connection established from 177.71.207.161
21:48:47 ovpn,info TCP connection established from 54.228.16.1

I think that this attacks pervents my connections.
So i put a simple rule like /ip firewall filter add chain=input src-address-list=BAN_IP action=drop, and put all this IP’s in this address-list. And it does nothing. Tik didnt block any connection from those IP’s.
I have 2 providers, i tried to create 2 rules, for each of providers, but it still didnt work.

What do you think? Where is my mistake?
Sorry for my english, it is not perfect.

The log doesnt actually say anything. besides there are many port scanners / telnet from the internet. You can try changing if you are using default port.

You can try logging your connection via input passthrough and try to debug whats happening.