Mautic API Basic auth - cant get it to work

Your software
My Mautic version is: 4.4
My PHP version is: 8.0
My Database type and version is: Maria 10

Your problem
My problem is:
When trying to connect to the API with Pabbly or Zapier via Basic Auth I can’t write new contacts.

Pabbly can connect and fetch the fields, but it cannot write.

These errors are showing in the log:
Pabbly says:
{ "errors > 0 > code": 400, "errors > 0 > message": "verifizierung: Dieses Feld ist erforderlich", "errors > 0 > details > verifizierung > 0": "Dieses Feld ist erforderlich" }

translation: verification is required

Steps I have tried to fix the problem:
Activated Basic Auth
Cleared Cache 100 times
Set app/config/sequrity.php to:
‘api’ => [
‘pattern’ => ‘^/api’,
‘fos_oauth’ => false,
‘mautic_plugin_auth’ => false,
‘stateless’ => true,
‘http_basic’ => true,

I cannot get this to work, stuck since 4 days.
Any ideas anyone?

Do you have any other security software on the domain - e.g. wordfence, mod_security - which might be blocking these requests?

Thank you. Not to my knowing, but I will check, I did not think about that at all.