Common errors or issues:
Here are some issues we’ve come across that cause this to happen:
One of the best tools for searching for errors in the HTML page headers is to use Firefox with the Firebug plugin or any browser developer tool. Turn on the console and check the responses tab under console for any errors. We have resolved many client installation and map problems with this plugin. More often than not we are finding errors in other plugins, themes, or server/site configuration settings.
Update your WordPress environment and review the WordPress changes.
Review the suggested new and improved requirements as of 4.9.
- Update PhP to 7 or higher
- Update MySQL to 5.6 or higher
- Site move to HTTPS