Supported server providers
OVH (starting € 84,99)
Connect both Dedicated OVH gameservers and normal dedicated OVH servers.
SoYouStart (starting € 34,99)
Connect both Dedicated SoYouStart gameservers and normal dedicated SoYouStart servers.
Hetzner (starting € 34,-)
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