Solution:
Option 1: Examine what other plugins you have installed.
Perhaps one of them is interfering e.g if you have cache plugin, you might want to clear your browser cache and try again and/or disable the cache plugin entirely
Option 2: Disable and re-install
If you have access to the host account, you can disable and re-install the plugin via phpmyadmin or ftp as shown in the following article. https://kinsta.com/knowledgebase/disable-wordpress-plugins/