Flashing red and green, no error message

I've bought a few Tonieboxes from returns pallets, most of them are working fine just been a bit of time connecting them for the first time.

But one fault I can't seem to fix is when it doesnt do the "hello" message, and flashed green and red without any obvious pattern.

Anybody have ideas what the issue is and is it able to be resolved?

Thanks in advance

Dave W