Have you seen %20 in your links? This is caused from a space in the name of a site or app when it’s created.
It’s helpful to understand how to read links in SharePoint Online because it can make your navigation super fast once you figure it out. To fix this, put the words together with capital letters for each word, then separate them afterwards. If your lists and libraries are already created with spaces in them, you won’t be able to change them afterwards, you’d have to recreate them.
The site creation screens cater for both the display name and link, so just wangle the URL Name for subsites. New modern site collection automatically keep the spaces out of the URL.
In the apps – go to List / Library Settings and List Name, Description and Navigation; and put the space back into the name.
Your link will now be easily legible, and name on the front-end friendly for users.
Same thing with the views you create in apps. If there’s more than one word, which there usually are, modify the view afterwards and remove the space in the link.
See how easy it is now to read where you are in a site. The stuff you build in SharePoint will likely be around a long time, do the right thing from the beginning and it becomes part of your legacy as a brilliant Site Owner and instilling good governance.