The problem is that the Cloudflare user mobisystems.com uses a wrong A-Record (18.104.22.168). This IP is owned by Sendgrid for sending out emails. Reverse-lookups are performed to this IP, e.g. from our domain eventyay. com when using Sendgrid.com. As Cloudflare shows the A-record for mobisystems. com Emails are rejected or are marked as Spam.
Solution: mobisystems.com needs to remove the wrong A-record.
Below I am adding the info from our Google cloud support and Sendgrid support. Please remove the A-record 22.214.171.124. It is not owned by mobisystems.com, but by Sendgrid as the below excerpts from Google cloud support and Sendgrid support confirms.
How can I reach Cloudflare, so they can work this out with the user?