How to fix this error ‘String contains an invalid character’?

I’m creating an Ecom dress site and added bootstrap cards and for each card if I clicked it I routed the site to specific page related to it, initially i can load the site but it was followed after by my front site, that is if i click a card called nike, Nike file was opening but followed by my entire front site, and later i made a seperate page for routing and when I run the program I’m getting ‘String contains invalid character error,how to fix this?

I need to go to seperate .jsx file when I click the card.