Minecraft server connection issue Access denied then connection timed out

I want to start a minecraft spigot server with my internet friends, but whenever I try to test to connect, it gives me an error.

I’ve added the port to the firewall, but whenever my firewall is active, I get the error: io.netty.channel.AbstractChannel$AnnotatedSocketExeption: Permission denied: no further information.

When I test with my firewall off, I get the error: netty.channel. ConnectTimeoutException connection timed out.

I am also using my external or public IP address in the following format in minecraft:
2##.###.###:25565

I have no idea how to really port forward properly and don’t know if I did it right. I’m using a Mikrotik router and I’ve added a NAT rule for port 25565 to forward to 192.168.0.21 on tcp and udp. In the firewall I added the port 25565 in the outgoing and ingoing sections via new rules, with tcp and udp.

I’m not a networking specialist at all so pleaaaassee can you help me.