I run a production email server on Digital Ocean and have not experienced this issue.
An issue I have experienced is that one email provider (who provides a white label service so that small regional ISPs can include a free email account to their customers) has blocked anything coming from DO's IP block. Ultimately my solution is to route those emails (and only those emails) through mailgun.com. The other 99.9% of my outbound email gets delivered directly to the final email server with no issues.
An issue I have experienced is that one email provider (who provides a white label service so that small regional ISPs can include a free email account to their customers) has blocked anything coming from DO's IP block. Ultimately my solution is to route those emails (and only those emails) through mailgun.com. The other 99.9% of my outbound email gets delivered directly to the final email server with no issues.