Cannot ‘Add New’ announcement

Hi,

I have installed version 8.7 of horizontal scrolling announcement plugin successfully to my wordpress site (a multi-site). When I attempted to add new announcement from Settings->Horizontal Scrolling page, after I clicked Submit button the announcement was NOT added to the list of announcements, and hence nothing is shown in the page.

Could you advise any fix or troubleshooting steps to assist me resolving this issue?