Hi there! Welcome to the community.
I downloaded your map and gave it a quick run through. First thing I noticed is it's fullbright. That means you don't have any light source. When fullbright maps are tested on the server, it can cause some problems (as well as just looking ugly

), so make sure you throw some light entities in there. Here's a tutorial on that:
https://developer.valvesoftware.com/wiki/Lighting
Another thing I noticed is players can get into the enemies' spawn. This isn't good, for reasons I won't explain.

Also your resupply lockers aren't correctly set up. I'm unable to get any health/ammo from them. Here's a great tutorial for properly setting up a spawn room:
http://forums.tf2maps.net/showthread.php?t=198
These are all common beginner mistakes, so don't worry, you'll figure it all out! If you need help with anything, don't hesitate to ask. There are a lot of great beginner tutorials here, so be sure to check them out.
