mixed content problems on my multisite

Hi, I was having trouble logging in to my multisite and found there were mixed content problems. I have a ssl certificate and have been using and seeing the green https address successfully. All of a sudden I have problems logging in. My host (wpengine) found the mixed content problem and did a search and replace changing the https in the site url for the subsites to http……I was able to log on but now the upfront editor isn’t working. I went in and replaced the url in the wp-options table of the sub site back to https. I was able to use upfront editor but when I logged off and then tried to log back in…no luck. I want the main site and the sub sites to use https……My host is able to support this. Again, everything was working in the past. not sure how to resolve this disconnect.