How to setup CiviCRM to proper send authenticated (DKIM) emails?
Is CiviCRM using the mailbox i configured for sending out the email if the email address is the same, or do i need to change anything else


For outbound mail, CiviCRM uses whatever you have configured at Administer > System Settings > Outbound Email (SMTP/Sendmail). How do you have that configured?

From a quick look at the source code of the email you linked to, my best guess is that you have it set up with the mail() option, which is likely not going to handle dkim (though that does depend on your webserver set up). If you have SMTP details for tickets@yogamela.org you could choose SMTP option there, add your details and then your SMTP server will then take care of DKIM.

Choosing SMTP and adding your details is likely the simplest route if you want to just get it working. That said, there are a few different ways that outbound mail can be configured so it is hard to give the best advice without knowing a bit more about your set up. Answers to questions like:


Who provides your email?
Do you want to email from multiple addresses or just tickets@yogamela.org?


would help provide a better answer.

Depending on your email provider, the SMTP details you have may allow you to send email from any email that ends @yogamela.org. Otherwise, if you want send email from lots of different email addresses ending @yogamela.org, you might want to look at a third party provider like Sparkpost or Sendgrid.

UPDATE:

That error message you pasted is a a bit wrong. The text does not match with the link. The text references FROM Email Addresses (civicrm/admin/options/from_email_address?reset=1) but the link you shared points at /civicrm/admin/domain?action=update&amp;reset=1. What do you have set in /civicrm/admin/domain? (see picture below). Try adding tickets@yogamela.org there.

I suspect it will then work.