When Activated causes lots of display errors

I installed your plug-in and then open another browser and all was well. When I activated your plug-in my we page displayed a list of errors from the plug-in index see below…

Notice: Undefined index: display_counter in /My/Local/Server/wp-content/plugins/e-mailit/emailit_widget.php on line 92

Notice: Undefined index: mobile_back_color in /My/Local/Server/wp-content/plugins/e-mailit/emailit_widget.php on line 109

Notice: Undefined index: hover_pinit in /My/Local/Server/wp-content/plugins/e-mailit/emailit_widget.php on line 133

Notice: Undefined index: logo in /My/Local/Server/wp-content/plugins/e-mailit/emailit_widget.php on line 148

Notice: Undefined index: mob_button_set in /My/Local/Server/wp-content/plugins/e-mailit/emailit_widget.php on line 157

Notice: Undefined offset: 1 in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1182

Notice: Undefined index: eventbold in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1208

Notice: Undefined index: eventitalic in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1209

Notice: Undefined variable: eventbackground in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1227

Notice: Undefined index: caldaytext in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1251

Notice: Undefined index: use_custom in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1281

Notice: Undefined index: cata in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catb in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catc in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catd in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: cate in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catf in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catg in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: cath in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: cati in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

Notice: Undefined index: catj in /My/Local/Server/wp-content/plugins/quick-event-manager/quick-event-manager.php on line 1285

These were displayed at the top of my front web page.

When I deactivated your plug-in these messages were not displayed when I opened a new browser to my web site.

I assume somehow these two plug-ins and yours are conflicting.

https://www.ads-software.com/plugins/login-form/