Hi Ashleydlf,
We're glad to help! It sounds like you may be able to go online on your Apple TV device when trying to connect to the Wi-Fi in your hotel, as there is no password entry field presented. Is this correct?
If so, it may be expected behavior, as hotels often utilize what are called captive networks. This is a Wi-Fi network that require some additional information, confirmation, or possibly payment to join. Apple TV doesn't support captive networks.
The following Knowledge Base article has more information:
Get help with Wi-Fi networks on your Apple TV
If you're experiencing this issue when attempting to sign in and use the Apple TV app on your iPhone, let's verify that your iPhone is able to access all other online content without issue. For example, you'll want to open some websites in Safari to verify that they load without issue.
This instruction guide has steps to help with setting up Apple TV app:
Set up the Apple TV app on iPhone
Let us know if this information helps, or if you've got any questions.
Thanks for using Apple Support Communities.
Have a great day!