To what extent is the sermon attributed to Imam al-Ridha, from Ali ibn Abi Talib, authentic, which its publishers claim to be a sermon by the Prophet, peace and blessings be upon him, welcoming the month of Ramadan?

This sermon has not been found in the authentic books of Hadith, and it is likely fabricated and attributed falsely to the Messenger of Allah, peace and blessings be upon him, due to its containing elements that contradict sound عقيدة (creed), such as exaggeration regarding some Companions. However, some of its paragraphs are supported by authentic hadiths, such as the opening of the gates of Paradise and the closing of the gates of Hell in Ramadan.