Trouble emailing PDF attachment

Hello, I'm trying to send emails with an attached copy of a record.

I've read many of the threads, and I've tried using "do as server", but I get an empty attachment when I do it this way. Here is my code. Please let me know if I can do anything to make this work. I'm inside the Ninox app, but using a Ninox account. When I run it without doing as server, I get an error that the file is not yet available, and when I do as server I get a file called "attachment-1.*". I have no problem if I try to send a file that's already created and attached to a record.

Thank you,

Matthew

if Students.'Email practice plan' = true then
let myName := "Lastlesson.pdf";
do as server
let thefile := null;
importFile(this, printAndSaveRecord(this, "Lessons"), myName);
thefile := file(this, myName);
let myEmail := text(userEmail(user()));
sendEmail({
from: myEmail,
to: "aaaaa@bbb.ccc",
subject: "Practice plan " + Students.'Student First Name' + "(" + LessonTime + ")",
text: "Here is this week's practice plan",
html: "<i>Here is this week's practice plan </i><br>Matthew",
attachments: thefile
})
end
end