We have setup two rules using Project Automation in JSD.
Rule 1 adds a number people to the Request participants field
Rule 2 sends an email to "Request participants".
Rule 2 works intermittently. When it doesn't work the error in the audit log is "Could not send email, the 'To' address field is empty. If you have referenced a field it may be empty". This rule is also set to trigger following rule 1.
Can anyone explain why this is occurring and how to resolve?
See screenshots below.

