Impossible to tweet a public message

Hello
I want to send a tweet with my account.
So, I have created an account, an API in Twitter, inserted the tokens, etc...

I can send a private message (direct) with a simple inject node with the syntax D user message
But I can not send a public message.
sometimes it works, but I don't know why.
I try to send just user message but the Tweet out return a 'failed'.

Is it possible to send public message on my account? How?
What are the restrictions
The error in the debug window shows : Status is a duplicate.
Thanks for your help

"Status is a duplicate." - means that you can't send the same message more than once... it ignores duplicate messages ... you must make each payload unique.

Thanks a lot.