Resolve the document conflict first
Send the installer photographs of the display, indoor and outdoor model labels if safely accessible, and the manual page you used. Ask them to provide the official document and revision that cover the installed combination. Have them explain whether the displayed E1 comes from the indoor head, controller, or another component and how their interpretation matches that source.
Record the operating mode, outdoor temperature, room temperature, time to shutdown, and whether other heads keep running. Do not repeatedly restart the unit to recreate the fault, open covers, check terminals, or bypass a protective function.
Require a finding, not a weather explanation
If the matching official table identifies communication trouble, ask the qualified technician to investigate that fault and document the result. If the installer instead cites an operating-temperature limit, ask them to show that limit and explain why this particular code and shutdown fit it. Both the code meaning and the operating conditions need to agree with the explanation.
We would want a report identifying what was tested, what was found, any correction made, and how normal operation was checked afterward. A suggested board or wiring repair needs evidence beyond the code alone. Electrical testing and connections belong to qualified providers.
If the original installer cannot explain the contradiction, request manufacturer technical support through the provider or an independent qualified ductless diagnosis. Keep the installation records and written coverage together, and clarify responsibility and charges before more work.
Your next step: Request the exact official fault table and a written reconciliation. Keep the affected unit off if it is repeatedly faulting, and arrange qualified diagnosis rather than treating recurring shutdowns as established normal behavior.