Hi, @Paul_Haze. We have a support guide about moving to Netlify DNS and preventing email downtime here:
There is a section about what to do when email services break because the required DNS records were not manually copied in advance.
The solutions are to either copy the missing records to Netlify or reverting to the previous DNS service and using the external DNS instructions instead of Netlify DNS.
If there are questions about either solution, please let us know.