(Posted this on ubercart.org a while back, but have gotten 0 replies - maybe someone here might have an idea. Thanks for even taking a look!)
After checking out and returning from Paypal Payments Standard, the user is not logged in and doesn't see the checkout complete page. They end up on the cart page with an empty cart (which is also the url for when an order is cancelled from paypal). Everything else goes through fine - they get an email, payment is made, all good. I'm using login toboggan. I just ran another test and saw the /checkout/complete url briefly, but then get bounced to the cart page very quickly.
Here are my checkout settings:
X Enable anonymous checkout.
Disable this to force users to log in before the checkout page.
O Allow anonymous customers to use an existing account's email address.
If enabled, orders will be attached to the account matching the email address. If disabled, anonymous users using a registered email address must log in or use a different email address.
X Require e-mail confirmation for anonymous customers.
X Allow new customers to specify a username.
X Allow new customers to specify a password.
X Send new customers a separate e-mail with their account details.
X Log in new customers after checkout.
X Set new customer accounts to active.
Uncheck to create new accounts but make them blocked.