Hi @Autism,
Unfortunately, apply to each action can only set 50 simultaneous runs., send Email with options will pending until the Email option is answered. The next 50 Emails will not be sent until the above 50 Emails are responded. So, send Email with options is not a good choice for 1200 Email requirements.
As an alternative, you can send these parents a Microsoft Form, with options to fill in, as well as the name Email address and other information, and remind them not to enter the wrong Email. Then create a Flow with trigger When a Microsoft form submits, and then go to SharePoint list to find the corresponding Email address, and update the item. If the email, is not found, it will send you a failed email, to tell you who filled in the wrong information, which needs to be re-filled in.
Best Regards,
Community Support Team _ Lin Tu
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
