Sites not viewing correctly in mobile

I’ve spent to much time trying to figure this out, perhaps someone out there with a fresh pair of eyes and a few helpful minutes can pinpoint the problem for me easily. I have been using the twentyfourteen theme for most of my resent sites because its responsive and easy to customize.
I have ran into some issues with my last two sites, and I must have changed something incorrectly. I’ve tried so many things to try to correct it and went over and over code for countless hours.

2 of my recent sites are not stretching correctly viewing mobile, while 2 I have done in the past are perfect. I thought it was the max-width, but that doesn’t appear to be the issue because that is set correctly.

the 2 sites with issues are: https://whitetaillandsales.com & https://www.bcertaininspections.com/

The 2 sites that are perfect are: https://www.greatergrandrapidsrealty.com & https://freshlookhomes.com/

There has to be an error in my css somewhere. Any helpful insite or tools to help me figure this out would be beyond helpful. Very important to have these stretch correctly in mobile!!
Appreciate anyones time.