As mentioned here: https://developer.atlassian.com/cloud/jira/platform/rest/v3/api-group-groups/#api-rest-api-3-group-member-get
Response of https://[domain].atlassian.net/rest/api/3/group/member?groupname=[groupname] should have field emailAddress. But all I got is: https://d.pr/i/5ASlmJ
I tried to add “expand” and “fields” params with “email” and “emailAddress” value without success. Was the field removed on purpose?