Auth.net completed transactions showing as Pending (Incomplete Transaction) - sometimes
There were some issues with Authorize.net transactions failing due it not managing to send an email- could that be related? Is email always required on the page? I think there are a.net fixes in both 4.7.18 &amp; 4.7.19 (still in rc) so it might be worth checking if a point upgrade changes anything (4.7.19 is due out first Wed next month)