A question about hosting a CS:GO server

I wanted to host a CSGO server to maybe spin up from time to time to play, some usual scrims and maybe some hide and seek maps, but then when I'm running the server, I can't open CS as Steam thinks it's already up. Did anyone have a similar issue and what did you do?

For scrims I would suggest you use popflash as its a nice and free site to use. On custom maps tho im not to sure why your not able to start cs while running the server.