After WHMCS 6.2.0 update, "clientportal" tables are not loading

After upgrading WHMCS to the latest version (6.2.0), none of the Domains, Services, Billing, or Support tables (e.g. My Domains, My Services, etc) within the "/clientportal/clientarea.php/" pages are loading the information from WHMCS. The loading icon just spins indefinitely (see screenshot). I am running "WHMCS Wordpress Integration 1.3"