Hi Rfla,
Were you using Office 365 outlook sending an email?
In the flow I created “when a new tweet is posted, send an email with Office 365 outlook”, in the send email action, I filled several email addresses in the To box. Of course, I used a semicolon to separate the several email addresses, and it worked well.
So when you want to send an email to one or more recipients using Office 365 outlook, separate multiple email addresses using semicolon would be useful. Before it is fixed, you could use a semicolon instead of a comma.
Best regards,
Mabel Mao