@crismoreno666 :
I do not know the subdomains, I’ve ever used, I thought that it could create emails via his Web host, for each subdomain.
I haven’t seen that Contact Forms 7 work for WordPress Multisite
the author, I think no other solution offers
https://www.ads-software.com/support/topic/red-border-error-issue-on-wordpress-441?replies=1
Which email address should you use in the From field? You should use an address belonging to the same domain as the site. The best practice is using wordpress@{your-site-domain} and preparing the address on your host.
You might be wondering why you had been able to send mail even with invalid mail setup. Why did this issue suddenly start with WordPress 4.4.1? We’re not certain, but the important thing is that mail header fields must have valid values regardless of WordPress versions. This is a good time to review your mail setup.