I searched and found many DM issues, but not this one.
DM is sent
Flashed message, The user, tweet, or page does not exist.
Steps to reproduce
Go to the users page. Tap ellipsis in top right. Tap Send DM.
User follows me and I follow them.
Android version: 8.0
App version: 3.7.3
The text was updated successfully, but these errors were encountered:
This works on my end. Try using the official keys (remove account from Twidere, enter official keys as linked in your post, re-create account in Twidere). There has been a point where Twitter removed some DM support from the API for third-party apps... with one of these keys, Twidere looks like the official app on API level.
I've just switched from Twidere(*) keys to Twitter for Android official app. ones (as linked in your post). And it works fine: DM, even with pic., sent&received, notif. with answers&fav.
(*) v. 3.7.3 from F-droid running on Android 6.0.1