HOA due prior to trustee's deed

I purchased a house thru foreclosure auction last month. Now as I’m trying to sell the house, HOA says there is a back due of over 1k. I have no issue with paying the hoa fees since the date of purchase/auction. But shouldn’t the bank/former_owner pay off the back hoa fees?

The laws may vary from state to state. In CA most HOA’s are typically not a “super senior lien”. This means that any past due dues are junior to the Deed of Trust. The previous owner may still be responsible for the past due dues but the new owner is typically only responsible for the dues from the date of the purchase forward.