I'm having this weird issue, that my client is not able to sucessfully send correctly filled forms.
However, I can fill and send them correctly every time.
I use wpmail smtp and can successfully send myself test e-mails and the forms mentioned of course.
How can I solve this? My problem is that I can't reproduce this behaviour but my client can.
I will try out postman tomorrow and see if I can get some information from that. I already checked the server error logs but didn't get a real help from there.