Is it for sure PHP 7.0 or is it PHP 7.1?
I would just go through general troubleshooting steps: https://docs.simplecalendar.io/troubleshooting-theme-plugin-widget-conflicts/
You might also want to just try uninstalling (make sure you keep the save settings option enabled) and re-installing if there are major issues.
PHP 7.0.17
I deleted and reinstalled the plugin.
I have switched to a default theme, deactivated all plugins and remove all widgets.
The plugin won’t activate and gives me the error of:
Simple Calendar could not be activated.
Required PHP Extension(s) not found: iconv, mbstring.
Please update to meet Simple Calendar requirements.
It is across the board on the server. All of my Simple Calendar installs aren’t working now.
It was working in the PHP 5.6 environment but now not in the PHP 7.0.17
Required PHP Extension(s) not found: iconv, mbstring.
Please update to meet Simple Calendar requirements.
You need to enable those extensions then for it to work.
Additionally here you can see all the requirements: https://docs.simplecalendar.io/system-requirements/
