Show Visual with cumulated Data by date

I have a list with dates of expiring certificates.

I would like to show in a graph how many certificates (y axe) are valid on a certain day for the next 2 years.
All I manage so far is to show how many expire on each day, but not the total number of valid ones.

Could someone help me out with a fucntion for this?

I tried this, but I get an error:

CALCULATE(
COUNTA(Brandschutz_ErsteHilfe_ItemStatus[Valid until],
FILTER(
All(Brandschutz_ErsteHilfe_ItemStatus),Brandschutz_ErsteHilfe_ItemStatus[Valid until]
>=MIN(Brandschutz_ErsteHilfe_ItemStatus[Valid until])
)))