Thank you for sharing your experience on digitalocean and OVH hosting providers. I want to understand the issue a bit more because we have a plan to host email service on both the platforms. Your inputs will help us to decide to go with them or to choose any other service provider. Can you please let me know when you sent those emails using both service providers is your emails authenticated with SPF and DKIM or you have used any free email service provider like gmail or yahoo as a from email address. Thank you in advance.