Steps to reproduce:

1. Go to your server, and get a file with a single quote ('), for example:

   file://test/atlassian/test's.xlsx
   

2. Go to your Confluence, add a page, go to Insert > Link > Web Link and past the above link.
3. Save it, and try to access.
4. You'll see that you won't be able to click on that.

Workaround:

For single quotes problem, you have to use the %27 in order to fix the problem.