I found my issue. In Chrome, for whatever reason, all error messages were simply "error" , so I tried Firefox where I have no extensions at all (because I don't as frequently use) and then it started to provide meaningful error messages. The address I tried to send to the first time was correct actually, and resulted in a "donation success" message, but when I tried sending to the account name rather than the account email (which had an underscore where an @ should be) I got: "coupon receiver ID not exist". So apparently "error" means something was blocked from working right, and if it comes up it will come up no matter what you do.