fish shop

Hey there! 🤗 I wonder how to get access to the backroom of Willy’s Fish Shop?? I have 10 hearts with him and fishing skill lvl. 10. Is there a specific quest that I need to finish? I haven't finished the community center yet, is that the problem? I hope someone can help me. thanks! 🙂

The message that pops up when you click on the ladder at the back of Willy's shop is missing a period at the end. This is in the English version and there are no mods installed.