Error problem

I am trying to create Let's Encrypt "your mailserver in poste.io and have tried everything enabled, also changed the judge. But I keep getting the same errors ([2020-12-15 20:21:19] LEScript.ERROR: Couldn't create directory to expose challenge: /opt/www//.well-known/acme-challenge/RPXDX4NGoHGFW8ue4pBf63AnBLDk2uDNwLkKsoLIQlo) .I'm using the latest images version. I don't know what the problem is.