Dear Stefano,
I am having the same issue… I thought it could be a problem of how I insert the codes, as the extension works fantastic just creating a category and adding the post to that one,
but I have tried adding the codes in every way possible.
I can get the Locked contain message, and the subscription form, but the contains I try to hide appear after, and I can see the code [/newsletter_lock] appearing on the web page, as if it is not understood by WP.
I am using text boxes, and it looks like if it only works when boths commands are in the same box.
But, if using the classic editor I edit the whole post in html code, adding the commands in several places, the content is not hidden…
Any ideas, please?
I have used the Search but I do not find any solution, please is there any link to a reply?
Thank you very much on advance!