Mautic to VTiger still the same error with lastname

Your software
My Mautic version is: v3.3.3
My PHP version is: 7.4.21
My Database type and version is: MySQOL

Your problem
Hello there!

My problem is:
I’ve activated the the VTiger plugin to push contacts to integration from my forms. Setting up the VTiger plugin in the Mautic went without any errors. I did contact mapping with only 6 fields, which you can see on this screen shot:

.
I have not mapped the field “Last Name” as it is not provided in my forms. My forms do not inculude this field!
I also added action to my forms to send contacts to VTiger and now, each time I’m sending any form this error occures in the notification tab:
"Vtiger error: lastname does not have a value"

Whats’s more. There are no errors shown in the log. The only error is shown in the Notification box and it states that "Vtiger error: lastname does not have a value"

Does somebody have a solution to this problem?

Waiting for any help,

Greg

If I am not mistaken, VTiger requires all contacts to have First name, Last name and email at a minimum