Error E1 on Rotenso Sole Air Conditioning S70Vi/S70Vo 6.4kW: Communication Issue & Troubleshooting

On the tmp display. error E1 appears. Rotenso Sole version S70Vi / S70Vo 6.4kW
According to the description, this is a problem with communication between the internal unit. and external
All cables checked.
Motherboard fuse approx.
Outdoor unit does not switch on.
The error most likely appeared after the night was turned off several times and the climate was in the heating option.
We know what it can be?

E1 is indeed a communication error between individuals. The question is what caused the power to be turned off several times (power surges or e.g. power line failure).
If you are an end customer, it is best to contact an Authorized Installer, and if you are a representative of a company from the HVAC industry, please contact our Service Department directly, we will conduct a diagnosis of the device.

greetings
Mirosław Cichy
Deputy Head of Technical Department
Rotenso Poland

info(_at_)rotenso.pl
facebook.com/rotenso