The Airtable support documentation doesn’t explain this anywhere, but Airtable doesn’t support lookup fields for its send email automations because a lookup field is an array instead of a string.
Yes, it’s strange that Airtable’s own automations won’t recognize its own array of email addresses, but the way to get this to work is to create a formula field, where your formula field is:
{Your Email Address Lookup Field} & ""
This formula will convert your array into a string. Then you can use this new formula field as your “send to” email address.
(BTW, note that Airtable’s automations are brand new and are still in beta testing. For more robust automations that give you more power & more control & more flexibility & scheduling capabilities — along with better error messages that explain where things went wrong — I would recommend turning to Integromat or Zapier. Integromat is more powerful & flexible & cheaper than Zapier, although it supports fewer applications at the moment.)
Hope this helps! If this answers your question, could you please mark this comment as the solution to your question? This will help other people who have a similar question. :slightly_smiling_face:
