In the Switch remake of Paper Mario: The Thousand-Year Door (TTYD), you won't be able to reach Rogueport West until you replace Zess T.'s contact lens. You can order a replacement lens from the Toad Bros. Bazaar store, but they won't ship for some time.
Where to find the contact lens in Paper Mario The Thousand Year Door – Access Rogueport West
If at any point during the prologue or Chapter 1 of Paper Mario: The Thousand-Year Door you attempt to go west from Rogueport Square, you will find Zess T. looking for her contact lens. She will tell you not to move, but of course you have to move if you want to continue playing the game. And inevitably, your next move will crush her contact lens. To punish you, she insists on blocking the path to Rogueport West until you buy her a new one.
Go to the Toad Bros. Bazaar, the store in Rogueport Square, very close to Zess T's house. Talk to the shopkeeper and he'll tell you that he's out of contact lenses at the moment, but that he can order some just for you. So, agree to order a lens and the shopkeeper will tell you to come back soon, but it really won't take that long.
I checked a few more times over the next few hours of play, and the Contact Lens still hadn’t arrived. What the store owner doesn’t tell you is that he’ll email you once the Contact Lens arrives, so you don’t really have to keep checking.