CyJervis re: sendgrid, this is what I have learned from the support team recently, when I inquired why I wasn't receiving email invites from our staging site:
This issue is happening because of your Reject DMARC policy, SendGrid and DMARC configuration isn't supported.
https://community.khoros.com/t5/Community-FAQ-s-from-Support/What-options-does-Khoros-provide-for-mail-delivery/ta-p/609592
And if you want to keep using SendGrid with DMARC, then you will have to modify your DMARC policy to none. If you want to keep using DMARC, you'll need to switch to DKIM, which will require use a subdomain that also doesn't match your community subdomain, like community-noreply@mail.community.XXX.com. However, if you use DKIM, you won't be able to use Email Metrics, as mentioned in the above docs. Request you to please refer the attached screenshot where SendGrid indicates a DMARC issue.