Supported server providers

OVH (starting € 84,99)

Connect both Dedicated OVH gameservers and normal dedicated OVH servers.
Website:  https://www.ovh.com

Recommended servers:

• https://www.ovh.ie/dedicated_servers/game/

Guides

• Prepare your OVH server to connect with GameserverApp

SoYouStart (starting € 34,99)

Connect both Dedicated SoYouStart gameservers and normal dedicated SoYouStart servers. 
Website:  https://www.soyoustart.com

Recommended servers:

• https://www.soyoustart.com/ie/game-servers/

Guides

• Ordering a SoYouStart dedicated server
• Prepare your SoYouStart server to connect with GameserverApp

Hetzner (starting € 34,-)

Website:  https://www.hetzner.com

Recommended servers:

• EX42-NVMe server (i7-6700)
• EX52-NVMe server (i7-8700)
• EX62-NVMe server (i7-9900K)

Guides

• Prepare your Hetzner server to connect with GameserverApp

Connecting unsupported servers

You can basically connect any server. Please do understand that connecting non-supported servers is a lot more complex.
Requirements can be found in this article: https://help.premiumark.com/article/60-non-supported-dedicated-servers