We are experiencing the exact same thing.
Everything was working fine, now all downloads produce a 404
Created new ones and they produce a 404 also.
Exact error message is: “Sorry, This Page Could Not Be Found!
The page you are looking for might have been removed, had its name changed, or is temporarily unavailable.”
Checked the permissions on the dlm folder but they should be fine.
Example: https://acrowood.us/emailfordownloadtest/
