Domains and SRV records, ports, proxies, Bedrock crossplay, whitelists and the many reasons a player cannot connect.
Most connection problems are one of three things: the address, the port, or the server not actually being up. Finding your IP and port settles the first two, and a server that shows online but rejects everyone is usually a whitelist or an online-mode mismatch rather than a network fault.
For a custom address, an A record alone is not enough unless you are on the default port. Connecting a domain explains when you need an SRV record instead, and why a new domain does not work immediately. Bedrock and Java players connect differently, which Geyser and Floodgate covers.
Every plan includes free Anti-DDoS and a dedicated port. If you are planning a proxy network rather than a single server, our Minecraft server plans can be sized per component.