This almost got me

[usonian]

20. Here's a rather thorough description of various email fraud techniques

How to Tell if an Email Is Fake: Red Flags to Watch Out For
https://powerdmarc.com/detect-fake-email-addresses/
Of course, it's also an ad for their product, which you can ignore.

Main tricks, inserting characters that look like the real ones, to fool you into thinking the source is a legitimate company.
The address does not have to "work". It's only there to fool you into clicking.

The above article is technical, but if you JUST LOOK AT THE PARAGRAPH HEADINGS, you'll get an idea of what's going on and what to be wary of.

Note: fake companies often game Google search to look like legit ones. For example, "HP Printer Service". They will get you to install remote control software.

In general, if you can't validate email addresses (and who can?) go the the REAL company site and find out what's going on, or not.

Sometimes, they're obvious.
Look at this piece of crap I got. I snapped the header, and didn't open it.