zerflin Alright so I dug into the logs and I do see that google is "accepting" the emails but they might be blocking them, they send via "email@example.com" and others so they might have blocked this.
Here is a log from one (redacted)
2019-08-23 08:12:01 T="Pagoda \"Reindeer Shatterproof Ornament\"" from <********@n11.nodehost.ca> for firstname.lastname@example.org
2019-08-23 08:12:02 Rc => email@example.com I=[188.8.131.52] F=<********@n11.nodehost.ca> R=dnslookup T=remote_smtp S=1321 H=aspmx.l.google.com [184.108.40.206] X=TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128 CV=yes DN="C=US,ST=California,L=Mountain View,O=Google LLC,CN=mx.google.com" C="250 2.0.0 OK 1566547922 o9si1337929qkg.190 - gsmtp"
2019-08-23 08:12:02 Rc Completed
The short of it is that Google accepted the message, but I think your form used to send your self spam as I see subjects with things like below is making them block it.
Top 5 CA Casual Dating Sites 2019
Welcome To The Last Video Maker You\342\200\231ll Ever Need
How would you use $30,000 to make more money
Meet a sexy girl right now
Look what we receive an eye to you!
This is all real subjects used to send to firstname.lastname@example.org