The problem occurred in La Quiaca, a border town between Argentina and Bolivia.
The day before I left, I tried to refuel, but the battery was weak and the engine wouldn’t start.
I just replaced the battery a few days ago so the battery should be fine.
I googled it and it seems like the regulator is probably broken if the battery won’t charge.

This
The regulator is supposed to convert electricity into heat and release it to stabilize the voltage and avoid excessive storage while driving.

This is sensitive to heat and seems to break easily.
Fortunately, there is a Mercado Libre in Argentina, so I searched for it and ordered it.

The price at this point was about 30 USD
It was supposed to arrive in 3 days, but since my 90-day stay in Argentina was approaching, I decided to go to customs to see if I could leave my motorcycle behind and leave the country.
When I explained the situation, I was told that I could leave my motorcycle there and leave the country, so I asked to have the regulator picked up at the hotel in La Quiaca and decided to go to Bolivia.

A few days later, my package arrived and I returned to La Quiaca.



This is not a genuine part, but it looks almost the same.
I will do the replacement in the customs parking lot.

The photo is out of focus, but all I did was remove the screws and connectors and replace them.
The battery wasn’t charging, so I asked the owner of the inn to jump start it, and the engine started.
After this, I drove a little and confirmed that it was charging, so I headed for Bolivia.
A battery that has once discharged is useless, so I need to replace it, but I was told that it is not sold in La Quiaca, so I will buy a new battery in the neighboring town of Villazon.