Hey, hang on a minute , you switched to ServeLink and at the same time two major browsers changed the way they indicate secure and non-secure pages. This has nothing to do with hosting and everything to do with browsers - it's part of this process: https://security.googleblog.com/2016/09/moving-towards-more-secure-web.html
PHP 7.1.16 is fine, you also have PHP 7.2.4 available which is the very latest build.
Hi Merritt, have you checked with the host to make sure the SSL cert is installed correctly, the php version is good. As for traffic that can be affected by any number of things. Check that Google Analytics and Google search console are both using the https version of the site .
No disrespect to Servelink, I am getting the server response I was looking for with them. And they just re-set those HTTPS re-directs for me, I was having trouble with Plesk.
Just baby-stepping thru the problems and deficiencies of my webstores.