prevent sending email when no recipients

go/internal/network/service.go

@@ -284,6 +284,7 @@ func (s *serviceImpl) AcceptInvitation(ctx context.Context, networkID, email, hu
 			}
 		}
 
+		if len(emailRecipients) > 0 {
 			newMemberEmailPrefix := strings.Split(normalized, "@")[0]
 			_, err = s.aeroSvc.ShootEmail(ctx, &pbaero.ShootEmailRequest{
 				ToEmails: emailRecipients,
@@ -298,6 +299,7 @@ func (s *serviceImpl) AcceptInvitation(ctx context.Context, networkID, email, hu
 				flog.Warn("unable to send email notification", "email", email, "network", network.Name)
 			}
 		}
+	}
 
 	s.mirrorAddMembership(ctx, humanId, networkID)
 	return nil