Trouble shoot problem

DIY
,
1

The Victron MultiPlus 48V 8000VA indicates an “Overload” fault even with no AC input and no AC output connected. It repeatedly attempts to start, detects an overload, shuts down, and then automatically restarts, repeating the same cycle

2

It is not end user fixable.
That is an RMA candidate.
Return it to a warranty centre for assessment or repair