In the old forum, topic Getting "Please Enter a Valid e-mail address" error, in post #85276 you've specified: "We will change the error message, we should rather display "You've already submitted 3 times the subscription form in the last 2 hours".
This doesn't seem to be the case in AcyMailing enterprise_v5.10.14, I still get the "Please Enter a Valid e-mail address" error while doing tests on https://news.silverado.nl/.
