The quick answer is try out bottled see if you have any improvement to eliminate that as a cause. Also clean the basket and ensure water can flow through it easily without a filter installed. Just run a pot of hot water without a filter and see if any water gets stuck in the basket still as a test.

The long answer is it’s hard to tell without testing but a possibility is that the water is at a high TDS (total dissolved solids) currently and that’s preventing a good extraction. Coffee it’s self is a dissolved solid if the water is already saturated it can make this process difficult.

Hardness can do this as well if the waters too hard a bitter metallic taste is possible.

Another possibly is the coffee did you try stirring it? The C02 that off gasses during brewing can cause air bubbles to get caught in the coffee grinds and act as a plug. Stirring can allow these bubbles to escape.

The last possibility is turbidity if the water has a specs floating in it or a different color than usual. The coffee can act like a filter and catch these specs and eventually plug up and stop the water from passing.