Classically, it’s a liquidity issue if the market value of your bonds goes down because rates went up, causing the discounted present value of the future maturity payout to decrease. It’s a solvency issue if the market value of your bonds went down because your borrowers turned into smoldering craters and they will not ever pay you back 100 cents on the dollar.

Really it is not so obvious to discern between them at the moment that the crisis is at its worst.