Putting the files in the web folder would work if you used a web browser to access your database but not from Filemaker. When connecting from a fileMaker client, your computer needs to be able to map and mount the location where the files are stored with exactly the same file path as is stored in the "by reference" container fields. This is not possible with your current method of connecting to your database.
You'll need to make some changes and each option has drawbacks:
Use VPN to connect to your database so that you connect as though a client of the local network instead of from a remote location.
Embed your files into the container fields instead of using "Store a reference".
Publish to the web using IWP and use a browser from nome.
Use SuperContainer (Expensive).
Thanks for your help! I setup a VPN and this problem went away.