Just as an addition to the given answer.
There are basically two reasons as to why scholars declared the hadith from Sunan abi Dawod as da'if: (I've add a transliteration/translation of the full narrator chain)
حَدَّثَنَا مُحَمَّدُ بْنُ عَبَادَةَ الْوَاسِطِيُّ، حَدَّثَنَا يَزِيدُ بْنُ هَارُونَ، أَخْبَرَنَا إِسْمَاعِيلُ بْنُ عَيَّاشٍ، عَنْ ثَعْلَبَةَ بْنِ ...
The hadith is basically correct in its meaning, similar authentic reports may be found elsewhere, for example:
ما أنزل الله داء إلا أنزل له شفاء
There is no disease that Allah has created, except that He also has created its treatment.
— Sahih Bukhari
إن الله لم يجعل شفاءكم فيما حرم عليكم
Allah has not put your cure in what he has made ...
Simply speaking this hadith is well known (one could say it is common knowledge), but when one starts checking the narrator chain one finds out it has flaws. Nevertheless seeking knowledge is regarded as essential for every Muslim. Scholars even defined a minimum of required knowledge which depends on the activities of a person, be it the ...