Unknown server tag 'nopCommerce:PopularTags'

Can someone possibly provide a cause of the above error. The Website returns an error when I attempt to access product categories, manufacturers, and topics. Products tags have not been added anytime recent. I am using Nopcommerce 1.60 and rarely occur any problems. I can also provide the complete text to the error if needed. Thank you for any help you can add.

hi, can you post the full error message, thanks