For security, SystmOne will only allow you to send to permitted email addresses or domains and by default it only has @nhs.net as a permitted domain. (What is a domain?^[1])

As secure email use increases it may be necessary to add other secure domains to those permitted by your unit.

Warning: You must ONLY add secure emails/domains to this list or you will put patient data at risk.
A list of secure address suffixes are below. If ever in doubt, raise a call for Clinical Systems Support Team.

Adding domains

• Setup > Users & Policy > Organisation Preferences
• Email & SMS > Email
• Click Add Domain
• Type @ followed by the secure domain. E.g. @suffolk.gov.uk or @suffolk.pnn.police.uk
• Click Ok to confirm and again to save the changes to Org. Preferences.

How do I know which domains are secure?

Certain domains are are always considered secure such as those ending .gov.uk due to security standards these services are required to meet. You can see the current list of domains on NHSmail's Support pages here.

There are other domains that may not be consider secure by default, but have passed NHS England's accreditation process, you can find the current list of these additional domains at: 

https://digital.nhs.uk/services/nhsmail/the-secure-email-standard#list-of-accredited-organisations