ANSWER:

This hadeeth with the addition that Allah will please him on the day of judgement is weak and not authentic. 

However, this thikr is authentic to be said after the athan and also 3 times with the morning athkar.  

Radheetu billaahi Rabban, wa bil-‘Islaami deenan, wa bi-Muhammadin (sallallaahu ‘alayhi wa sallama) Nabiyyan. Allah has promised that anyone who says this three times every morning or evening will be pleased on the Day of Resurrection.” I saw on twitter you said it’s authentic. You said to me via email it’s not few months back. Please confirm as I’m confused which is correct :)