.net driver; connections NEVER gets idle!

Hello all, my first post.

I am using neo4j to create a framework based on nodes and relations.

Opened my system today for a demonstration, for the 1000th time.
But this time the .net driver refuses to ever reuse a connection. So after 100 queries it says that:
"Failed to obtain a connection from pool within 00:01:00"

This is even a problem if I use:
WithMaxConnectionLifetime(TimeSpan.FromSeconds(10)) in the driver settings

I know that connections are reused and not closed, or disposed.
They just never become idle again. Something locks them.

I use both Session.Run and Transaction.Run with using. No difference.

I have checked the neo4j browser, and yes, all 100 connections are there. And stays there until I have closed my c# application. Never to be used again.
I can change the number of connections in the pool, to say 10, but the behavior stays the same.

It has been working for years. And today it decided that, nope, won't work.
( of course during a presentation )

Any ideas would be much appreciated.

/eric