DKIM, SPF, and DMARC have been set up for the domain ngo.helioho.st. We recommend sending a real email (not just the word "test" or a blank email) to https://www.mail-tester.com/ to make sure that everything is set up correctly. If you get less than a 10/10 score please post a link to the full report so we can help you fix any other issues that there may be.
Please keep in mind that there is a sending limit of 50 emails per day. If you need more, you'll need to answer a few questions regarding who and what you're sending and we can increase that limit.