Automate action - Add a record to sub-entity field error

[techtr]

Good day, I am building an automated action where I need to add a record to a sub-entity. I can assign all fields except "file" type field cannot be saved from the suggested fields. It is assigned, saved and comes back as empty. I have a very similar process in another entity that I had built several months ago and it is still working fine. Please see below. Both fields are exactly the same type, hence suggested by the system. Please advise what to do. Thank you.

[support]

"file" type can't be submited via ajax. Use Attachments file instead. In Attachments field settings you can limit file upload to 1 so it will work like single attachments field.

[techtr]

That worked. Thank you.