Question Bug with emails - not with Joomla settings

I am trying to have a second look at this for you. I am like you just a normal user who's trying to help you. I think the reason why you have had no input from others, including Kunena, is that they don't think that this is a Kunena problem and is either something to do with Joomla or your server/host.

Is this your own server either local or at a host, or have you bought shared hosting? The server appears to be a MS OS?

I did suggest that you speak to your hosting company, assuming that is what you are doing, and if so what did they say.

I note that the mailgun route receives from [email protected] and has a dkim and srp. The other route is [email protected] and has no dkim or srp. I realise that the actual sender is =inspry.com but which account is actually opening the connection to gunmail and has accepted mail from both the ngo and ong domains? (I have checked and all three domains are registered and active.) You have to create dkin and srp thouhg I would imagine that gunmail has done this for you. The other one with no dkim or srp is possibly as one has not been created. You cannot get these with phpmail and as I mentioned in a previous posting I don't know of a host that uses it even when set up. They usually pass it through their own smtp server but will not have a dkim or srp. Are you having mail bounced?