I cant join my friend in astroneer it keeps saying "cant connect to host"

hello yes it is only one of my friends with the problem and we are on Xbox series s

It can be an issue with the game itself. Kindly ask your friend to perform an extended powercycle and reset the network hardware by following the steps below:

1. Unplug the power cable from the back of the router, modem, or gateway for 5 minutes. If you have a router and a modem, unplug the power cable from both devices.

2. Press and hold the Xbox button on your console for 10 seconds or until it turns off then wait for 2 minutes before turning it on again.

3. After 5 minutes, plug the modem or gateway in first, and wait for all the lights to return to their normal state.

4. If you are using a router, plug in the router and wait for all the lights to return to their normal state.

yes we can play literally any other game except for that

Perfect. Were you able to play with him on a different game?

It may mean that it's on your friend's end. Kindly ask your friend to check his/her NAT Type. Make sure that it's OPEN.