Right click and Open In New Tab works as a workaround, but that's because when you open a link that way, it's ignoring the iframe codes that are causing the problem directly from the published document.
That's however not a practical solution to tell lots of viewers to open in new tab - the code on the published document page needs to be improved to not restrict opening the link in a new tab - either by dropping the restriction (which then creates a security risk that obviously this setting is there to avoide) or by improving the options on the published document to have some API style features where you can allow particular domains to be 'whitelisted' for a document.
Right click and Open In New Tab works as a workaround, but that's because when you open a link that way, it's ignoring the iframe codes that are causing the problem directly from the published document.
That's however not a practical solution to tell lots of viewers to open in new tab - the code on the published document page needs to be improved to not restrict opening the link in a new tab - either by dropping the restriction (which then creates a security risk that obviously this setting is there to avoide) or by improving the options on the published document to have some API style features where you can allow particular domains to be 'whitelisted' for a document.