Not graded
Sunan ad-Darimi 623
أَخْبَرَنَا عَفَّانُ حَدَّثَنَا حَمَّادُ بْنُ سَلَمَةَ أَنْبَأَنَا أَبُو حَمْزَةَ الثُّمَالِيُّ عَنْ الْحَسَنِ قَالَ غَائِلَةُ الْعِلْمِ النِّسْيَانُ
This hadith has no English translation yet: the Arabic text, the reference and the grade are shown here.
Reported by Ad-Darimi (No. 623).