1
sagaga
Hello, a couple of things that may help solve your ongoing issues.
First in your original post you indicated PHP 7.3, I assumed that was a typo as cart v 1.4.1 only works on 8.2 or 8.3
You can check the PHP recommendations here.
https://abantecart.atlassian.net/wiki/spaces/AD/pages/3768390/AbanteCart+System+Requirements
Next, Gmail and Yahoo both started REQUIRING DMARC be enabled for your site. Here is the Google article
https://support.google.com/a/answer/2466580?hl=en