@mediapool
The 500 Internal Server error could be caused by a few things. If you can’t get to your settings I recommend you update your WordPress to the latest version, and also be sure your host is using PHP version 5.6 or newer. Then reinstall the plugin as follows:
– Perform a complete back up of your database before proceeding further
– Delete the file uninstall.php from the plugin directory that is currently on the server (found under /wp-content/plugins/all-in-one-event-calendar). Deleting this file ensures that when you uninstall the current version of the plugin, your event data and calendar settings will be preserved when you delete the plugin (don’t skip this step – it’s important!)
– Deactivate the All-in-One Event Calendar using your WordPress Dashboard.
– Delete the All-in-One Event Calendar using your WordPress Dashboard.
– Database -> wp_options, click option_name to sort and delete everything with ai1ec_, this will delete plugin settings but events will remain in the database.
– Now install the latest version.