Troubleshooting

Confirm System - Easy Responsive Tabs is enabled.
Check shortcode spelling: opening and closing etabs / tab tags.
View the published page (not only the editor). Clear cache and hard-refresh after changing the plugin.
For article tabs, use published article IDs the visitor can access.
If the editor button is missing, enable Editor Button - Easy Responsive Tabs and confirm the system plugin is installed.
Do not put raw {etabs} or {tab inside demo description text outside the live shortcode; the parser will treat them as tags.
URL changing on every click with many tab sets? Turn URL Hash Deep Links off, or use hash="false" on individual sets.