Tectite formmail php script error when migrating to https://

Tectite formmail gives an error when migrating to https://

After submitting the form, the browser goes to:

https://test.harrieboerhof.nl/templates/HB-home/forms/fmbadhandler.php?insession=1&vuyk=790dg132pl9sm33qcla6ho7dn5

And gives a white page with this message:

"insession specified, but no data found in session "

I receive a mail with subject "FormMail script error" and the message:

mail_failed ********** Error=Failed to send email

Plus a mail with subject "FormMail script error" and the message:

Socket error 0: :

When testing with https://www.harrieboerhof/templates/HB-home/forms/formmail-aanvraag-tuinontwerpgesprek.php?testalert=1 in the browser a message:

Test message sent. Check your email.

and a mail is received with:

This is a test alert message Loaded language is English (builtin) PHP version is 7.0.22-0ubuntu0.16.04.1 FormMail version is 8.24 Server type: non-Windows

DOCUMENT_ROOT: /var/www/testhtml SCRIPT_FILENAME: /var/www/testhtml/templates/HB-home/forms/formmail-zend-uw-bericht-test.php PATH_TRANSLATED: -not set- REAL_DOCUMENT_ROOT: /var/www

SERVER_NAME was localhost REQUEST_URI was /templates/HB-home/forms/formmail-zend-uw-bericht-test.php?testalert=1

User IP address was 81.206.125.28 User agent was Mozilla/5.0 (Windows NT 6.1; WOW64; rv:55.0) Gecko/20100101 Firefox/55.0

The html of the form:

<form action="https://test.harrieboerhof.nl/templates/HB-home/forms/formmail-zend-uw-bericht-test.php" enctype="multipart/form-data" method="post">
  <input name="recipients" type="hidden" value="harrie" >
  <input type="hidden" name="bcc" value="mail@domain.nl" />
  <input name="conditions" type="hidden" value="conditions" >
  <input name="subject" type="hidden" value="Contactformulier van website" >
  <input name="mail_options" type="hidden" value="HTMLTemplate=https://test.harrieboerhof.nl/templates/HB-home/forms/zend-ons-uw-bericht.htm, NoPlain, FromAddr=noreply@harrieboerhof.nl,TemplateMissing=-, CharSet=utf-8 " >
  <input name="good_url" type="hidden" value="https://test.harrieboerhof.nl/nl/zend-ons-uw-bericht-bedankt/" >
  <input name="bad_url" type="hidden" value="https://test.harrieboerhof.nl/templates/HB-home/forms/fmbadhandler.php" >
  <input name="this_form" type="hidden" value="https://test.harrieboerhof.nl/nl/contact-met-uw-tuinman-hovenier-uit-drenthe/contactformulier/" />
  <input name="bad_template" type="hidden" value="https://test.harrieboerhof.nl/nl/onvolledige-contactaanvraag/" />

When I use the http:// version of the testsite, everything works fine. I searched Google for this condition, but it seems to be the first time this happens, I hope someone has an idea what could be wrong?

Edit: the accepted answer is not quite the answer, look in the comments below.

I suspect the problem is that PHP sessions are not working as they should with your https://test site.

"vuyk" appears to be the session name.

So do you have

$SESSION_NAME = "vuyk";

in both FormMail and FMBadHandler?

If so, then it may be a problem with the configuration of sessions for your https://test site.