Ecoflow river overload problem

Ecoflow river device was used in UPS mode. At some moment (maybe AC input jump?) stopped charging.
If plugged into wall AC socket and enabled AC output at same time, not works:
- gives short AC impulses (lamp flashing), no indication;
- or shows “overload” + “50hz” flashing on display.
While disabled from grid, normally gives 220 AC output - however, there is no way to charge.
Wall socket (power from grid) is ok, my desktop PC works perfectly, so there is no problems with input power.