Hi, everyone

when I tried to publish a HIT, I received the following error: An error occurred (RequestError) when calling the CreateHIT operation: This Requester has insufficient funds in their account to complete this transaction. Please visit https://requester.mturk.com/prepayments/new to purchase Prepaid HITs. (1619107019145).

I tried to purchase prepaid HITs, but it seems that new mturk requesters can't use prepay, but they must sign up with AWS billing. And I have contacted the AWS services，they replied that "once your account is set on AWS billing it can not be changed back to prepay".

so how can I publish my HIT from Heroku to Mturk? Can I publish HIT without purchasing prepaid HITs? or are there some other ways?

I recall that other people who had this problem solved it by asking Amazon to increase their billing limit. If you search this forum you can find info on this.

Hi, Chris

I have contacted Amazon to increase my billing limit, but it seems that I still cannot prepay for HITs after that. The mturk service told me that “as of November 7, 2021, all Mturk requester accounts are created with AWS Billing enabled, and are on an all post paid system. It is not possible to prepay.”

so I wonder if it is possible that otree adopt the post paid system, i.e. AWS Billing, so that we new Mturk requesters can publish HITs to mturk successfully.

this is the reply of Amazon mturk:

"Please understand that once the AWS Billing payment method is applied this cannot be changed. 

Going forward, the AWS Billing payment method would be the only payment method to use as a Mechanical Turk Requester.

Historically, MTurk Requesters were required to prefund their MTurk account (with the prepaid method) and typically calculated the amount they would spend prior to creating HITs. 

Now, with AWS billing, you can sign up on MTurk, link your AWS account, enable AWS billing, and immediately start creating HITs. Removing the prefund barrier dramatically reduces the time to complete work and simplifies your procurement process.

This new feature should simplify your billing process across all AWS products and services and make it easier to track your expenses all in one bill. "

My understanding is that despite the error message, you don't need to prepay for your HITs. The real issue is that you have exceeded your billing limit. Search the forum and you will find more info.

hi, Chris
    Thanks for your advise, my monthly limit has been increased, and I can successfully publish my HIT now. However, a new problem comes. 
    When I published an oTree project from Heroku to MTurk, I did not receive any responses from real participants, and if there were any, they likely were robots that entered the completion code and submitted without actually clicking on the link. To verify whether the issue was with my account, I posted a survey on MTurk's backend instead of Heroku, and received responses from real participants, which I then verified were not robots. 
    Do you have any idea?