It had been awhile since I went through the painful process of developing HTML e-mails. I generally try to avoid it when possible (because Microsoft Outlook). I was recently tasked to create one for a client and I decided to give Foundation for Emails a try. It makes the process infinitely less painful.
Evidently, Google has an axe to grind, as you may now get the ERR_CERT_COMMON_NAME_INVALID page any and every time you try to load a page or click a link on a locally-developed site that forces SSL. This is how I (sort of) "fixed" it.
Chrome let's you add new emulated mobile devices by opening the Developer Tools pane (View > Developer > Developer Tools), going to Settings (F1) then Devices and clicking the Add custom device button. In this post, I will list some modern devices that you can add such as iPhone 7 and the Samsung Galaxy S7/S8+.