I’m able to replicate a similar issue locally:
Both MX Toolbox and AlienVault are reporting that a DNS record has not been created:
Additionally, running whois speckle-server-dgtra.com returns No match for domain "SPECKLE-SERVER-DGTRA.COM"
Please ensure that you have followed DigitalOcean’s guide to adding a domain to their system: How to Add Domains :: DigitalOcean Documentation
Iain