If you have any issues after an update, please open a support ticket. It the issue is severe and affecting all users, we will immediately start working on a hotfix which we make available as soon as possible.
If you want to switch back to an old version until this fix is available, please download a former version from https://www.mapsmarker.com/updates_pro/archive/ and overwrite the plugin files on your server in the directory /wp-content/plugins/maps-marker-pro/ (v4+) or /wp-content/plugins/leaflet-maps-marker-pro/ (v3.1.1 or lower).
Please DO NOT uninstall and reinstall the plugin to rollback to an old version, as uninstalling the plugin will also delete all map data!