theseven 003 is a loss of communication between the MASTER and AC modules. Try a full power cycle (disconnect all inputs and press and hold the power button for 15+ seconds), and if that doesn't help either, contact support@zendure.com about it.
TigerDan waited until now to upgrade AC, saw the same 003 error code, and does not help after 15 sec reset. Just wondering how Zendute resolved this issue?