A tax lien is different. The City of Saskatoon can move toward a tax enforcement process on unpaid property taxes, and how far your specific file has progressed toward that determines how much room is left, so calling the city's tax department directly to confirm your exact standing is the first real step, not a guess based on the notice you received.
In both situations, contacting your lender's special accounts group or the city early, before any court date or enforcement step, gives your lawyer regulated by the Law Society of Saskatchewan the most room to negotiate a sale, with legal fees on that work typically running $800 to $1,500, that pays out the arrears from the proceeds rather than losing the house to the process itself.
Time matters more than almost anything else here, so the first call should happen today, not after you have a buyer. Get your hand-reviewed valuation from Joel Dyck.