Problem :
I mistakenly upgraded to MAMP 4.2 free version. Now all my sites are trying to open with https:// which generate an error when trying to access to any of my local websites. I already checked hosts, httpd-vhosts.conf, httpd.conf files and they all seems to be OK. Need help! 
Solution :
It’s caused by the New Chrome Update 63. you have to change .dev to something else, .localhost or .test or something.
Look at this article here
https://ma.ttias.be/chrome-force-dev-domains-https-via-preloaded-hsts/