For example：
This address is valid:mc.hypixel.net
This address is invalid: mc.hypixel.net
This address is also invalid:mc.hypixel.net (There is a space at the end)

I think the value of "server address" should automatically perform TRIM to remove the first and last spaces, rather than leaving the player to handle it themselves.
If there is a space at the end of an address, it should be difficult for the average player to notice and troubleshoot.