Please make the full backup of your site and check the issue on the Storefront theme, if the problem occurs only on WoodMart, deactivate all the plugins not related to the theme provide the site admin access to the private area.
Hi,
if you have such problem just try to do this:
1. Go to settings
2. Open Direct links or direct URL’s, I have Polish language)
3. Change Direct product url’s to Default or to own format
It will work if you have “index” in name of product URL.