Netatmo, one account, two houses with two Home Assistant instances

Dear all,
I’m facing the following problem: I’m not able to use Netatmo on a second house Home Assistant instance.

I have two houses, in each house I have a MiniPC with Home Assistant installed in. So that each house has its own Home Assistant instance that is completely independent from the other.

I have two Netatmo Chronothermostats: one installed in each house.

I have one Netatmo account, where I registered the two houses and associated to each house its own Netatmo Chronothermostat.

In the first house, I have connected the Home Assistant instance to Nabucasa (paying regularly the annual fee) while for the second house I do not use Nabucasa.

In the first house the Home Assistant instance Netatmo works flawlessly.

The problem occurs in the second house, where I get the following error:

WARNING (MainThread) [homeassistant.components.netatmo] API error: 500 (Internal Server Error)

500, message=‘Internal Server Error’, url=‘https://account-link.nabucasa.com/refresh_token/netatmo

Anyone has the same problem and has any suggestion to solve it?

Regard,
VS