Please Go to Appearance >> Menus edit menu and make sure that the HTML Blocks are added as dropdown for the menu and also the click event is set to hover.
Then clear cache and check back.
If the problem continues then provide with the admin panel login details of the website to check it myself and help you out accordingly.
If you want to add a simple dropdown then you need to set the set width option to default and add items as sub items by editing the menu from Appearance >> Menus.
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