Electrostatics and Electric Circuit

I am relatively new to COMSOL. I am trying to simulate a two part problem.
1. An electric pole is placed underwater
2. A circuit is built around it to measure the voltage drop across a resistor

The setup can be better understood from my schematic that I have attached.

I have done the first part in which I ran the Electrostatics Physics and got the potential plot. From different posts in this forum I was able to make a little headway into the second part, but it does not work. I assigned two terminals 1,2. Added a voltage source between 1 and 2. Added a External I vs U between 2 and 3 and then a resistor of 10000 ohm between 3 and 0. When I try to solve this, I get the following error

Errors during multiphysics.
The DAE is structurally inconsistent.
- Variables: 2
- Equations: 0

I have attached my files.

The reason may be that the two terminals are not connected. But the water should technically close the circuit. And there should be a reading on the voltmeter. I have verified this experimentally to be of the order of 300 mV. But COMSOL does not solve my problem. Is there something that I am doing wrong or COMSOL is not designed to solve such a problem.

Any help will be highly appreciated. Thanks.