Muwatta Malik 462
موطأ مالك#462SahihYahya related to me from Malik from Nafi that Umar ibn al-Khattab said, "Any direction that is between east and west can be taken as a qibla if the person praying is face-on to the House
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Salim al-HilaliMauquf Sahih
In-book reference: 14:8