Email delivery issues


I am running a multi-part research study whereby I need people to use an app between each study.

I was advised by a prolific staff member that I would need to ask participants to register to our app using their prolific assigned email address, which I did.

When a user signs up to our app they get sent a confirmation email, and in that email they have to click an activation link.

Problem is that the participants are saying that the email confirmation email from our app is being blocked and they cannot activate our app.

Any ideas what is wrong or how to fix?



Hi Alan,

Welcome to the community - it’s good to see you here! :wave:

This sounds like it might be an issue with how email servers are interpreting the app’s verification emails but worth troubleshooting the whole journey:

  • Are emails from the app being sent out successfully? Worth starting here, as it could be an error on the outgoing server, or a limit on how many emails the app can send out in a given period.
  • Is there any pattern or trend in the users who have reported their emails being blocked? For example, are they all using the same email service (e.g. Google Mail, Outlook. etc.)? Did these users all register on a similar date/time?
    This’ll help determine if it’s an issue with a specific email service as well as when the service(s) may have started blocking your apps’ emails.
  • Are users who have reported the block able to register using a different email address? This will make it harder to identify study participants, but may help determine where the problem is.

It’s also worth trying the following steps:

  • Advising users to add the email address your app uses to send out verification emails to their safe senders / allow list.
  • Making sure the emails sent by your app are authenticated, as this ensures they’re less likely to be interpreted as dodgy. Google has a helpful page on this. This is configured at the domain level (and may already be done), so worth double-checking with your email hosting provider.

That’s pretty high level, but hopefully may provide a starting point. It may also be worth raising a support ticket with your domain host or email service provider, as they may be able to give more specific insight into your case.

Many thanks,