This could be due to a Facebook password, administrator or any other change on Facebook’s end. Navigate to the My Account section of your SnapRetail account. The My Account section is found by clicking on the icon at the top right hand corner (silhouette of a person) and then click Account.
Scroll down until you reach Email & Social Media Accounts.
Click Disconnect under Facebook.
Then click Connect and follow the prompts on your screen to relink your Facebook Page to SnapRetail.
Keep in mind it will ask you, as the Page administrator, for permission to connect via your personal profile. This is correct. Continue to follow the prompts to link your Page at the end, instead of your personal profile.