Digital ocean marked the issue as fully resolved now.

It looks like everything is back to normal right now, but Digital Ocean is still investigating on this. If this happens again, please use your default subdomain to access your admin project interface.

Digital Ocean is reporting multiple product failures at the moment: https://status.digitalocean.com/incidents/xkpsn9hbnnlz

Please, follow the above link to get updates.

There are problems accessing DatoCMS projects via custom domains.

We are going to investigate this, but in the meantime please use your default DatoCMS subdomain (<your-project-subdomain>.admin.datocms.com) to access it. If you do not remember your project subdomain, you can always check it out in our https://dashboard.datocms.com