New battery and alternator, van won't start

[Deak22]

So tonight battery was fully charged, tried jumper cable trick, still crank no start... Read codes and got p056200 plus a new one... P218f00 reductant no flow detected... Ad blue pump I think.
Cleared codes, cranked it, read codes and low voltage code has gone, p218f00 is back...

 

[Deak22]

So tonight battery was fully charged, tried jumper cable trick, still crank no start... Read codes and got p056200 plus a new one... P218f00 reductant no flow detected... Ad blue pump I think.
Cleared codes, cranked it, read codes and low voltage code has gone, p218f00 is back...

Ad blue tank is full, but countdown warning is on dash