Having enabled the setting “Receive Direct Messages from anyone” you receive dm’s from users that you don’t follow.
However when trying to reply to the message from these users via the “1.1/direct_messages/new” endpoint I receive the following error code and message:
"code" => (int) 150 "message" => "You cannot send messages to users who are not following you."
The call to the endpoint is done with the
user_id to identify the user during the request.
According to the docs this should be possible “Once a Direct Message thread is established between two users, that thread can be used to send messages bi-directionally, regardless of the follow relationship.”.
Replying on the dm with the twitter web app also works if this occurs.
We are facing this issue with several of our app users accounts but not all it seems. (The developers live )