Gmail permanently blocked me from sending outgoing mail after emailing only 16 house rentals on Craigslist

[Max M.]

I created a new gmail account to handle my internet marketing stuff for lease options, and as my first foray into the game I decided to mail some rentals/FSBO's in my area on Craigslist. What I figured I'd do is first hit up the rentals from 7 days back and work my way up to the front, and then do the same with FSBO's. Never made it that far ;)

I clicked reply and selected gmail on 8 ads yesterday and 8 today and sent a couple sentences saying I'm an investor and would they consider a lease option, if they're interested in having their home maintained while it gets sold, they should call me at my number. After that every single one of my outgoing emails on this gmail account was instantly rejected by gmail on a permanent basis due to their antispam setup. Essentially this gmail account is completely unable to send outgoing email, permanently.

Based on what I've seen, it seems 25 mails per day is a pretty small and reasonable number that many people subscribe to as being a decent marketing stream for Craigslist. And yet I do 8 per day and my email address is shitcanned ;) I find this most puzzling because I hear about hiring VA's to do 25 a day and even making a new gmail or other account specifically to share with them for this purpose.

Where did I go wrong? Is Craigslist not in the stars for me?