When you are on vacation you use Public Wi-Fi, see this Apple article: Use captive Wi-Fi networks on your iPhone, iPad or iPod touch
Use captive Wi-Fi networks on your iPhone, iPad or iPod touch – Apple Support (UK)
-> ask the hotel for a username & password to log in to their Wi-Fi.
Nowadays, Public Wi-Fi is offered for free, in big cities, shopping centers, in Public Transport (bus & train), restaurants and others.
Are you back home try to connect the Wi-Fi again to your own Wi-Fi network.
See the following Apple articles:
Connect to Wi-Fi on your iPhone, iPad, or iPod touch
Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support
If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network
If your iPhone, iPad, or iPod touch won't connect to a Wi-Fi network - Apple Support
Recommended settings for Wi-Fi routers and access points
Recommended settings for Wi-Fi routers and access points - Apple Support
If you need help with your Wi‑Fi password
If you need help with your Wi‑Fi password - Apple Support
If they are On, turn Off Hotspot & VPN.