Forgive my ignorance but I am new to using automations and cannot for the life of me figure out what's going wrong.

I am trying to set up an automation to do 2 things:
send an email
update a record

The trigger and email portions test fine, but I can't get the Update a Record action to work.

It seems to me that it must be something within the Field I want to update - I am trying to have it mark a checkbox once an email has been sent.

Any advice appreciated!