Unisender: subscription from the form on the site does not work with some iphones, what to do?

Question

Email Marketing

There is a form with Unisender on https://yulyabogdanova.com/vebinar-optimalnyj-sahar/ .
In most cases, it works fine and subscribers reach the goal.
But from some (many) iPhones people can't subscribe, although they fill everything in correctly. You can check with iphone.
They receive such an error as in the screenshot.

Everything works fine on Android and PC.

Initially, I installed the javascript version of the Unisender form.
Now there is an html-version "for developers". The result is the same.


Who faced? How to be? Unisender - because there are already configured automatic mailing chains, a bunch of contact lists.
Support cannot help with this.

Answer 1

I had to replace it with Sendinblue, now it works .