Hi. I just rented my Ark server. It isn't showing up on the Epic server list. Do I just need to wait until it populates there? I wonder what the wait time is for this? Thank you.

You'll want to make sure you don't have any mods added to the server, and have cross play enabled.

Note that ARK only polls 5000 random servers, starting with hosts who also host the Official Servers, and then spreading outwards to other servers, based upon geographic region, ping time, and IP address range.