Email address supporting plus addressing and multiple subdomains.
This expression follows the rules displayed at https://knowledge.validity.com/hc/en-us/articles/220560587-What-are-the-rules-for-email-address-syntax-. Note that their rules DO NOT exactly match those of the applicable RFC 5322 (sections 3.2.3 and 3.4.1) and RFC 5321, but rather supports a pattern ...
Submitted by Eric Bewley - a year ago