I have a newly created bot that I am trying to send PMs to users with, using PRAW function as reddit.redditor(user).message(subject=subject, message=msg) (only users that have opted in, no spam)

PRAW is returning an error message of RESTRICTED_TO_PM and User doesn't accept direct messages. Try sending a chat request instead.

I get this is a form of spam and bot prevention for a reason, and that I just need to wait to be able to send them as a bot user. But here's what I don't understand about that.

If send the same user a bot PM on the Reddit desktop site, it gets sent just fine with no errors. Using Reddit Is Fun on Android mobile as the bot user, I can successfully send the same user, the same PM message.

It is only my PRAW script that has this limitation of being blocked for sending a PM. Why is that? How can RIF send an API PM as my bot user, and bot user can send from the website, but my PRAW script can't ?