owner may be null even without error

src/reverseproxy.js

@@ -81,7 +81,7 @@ async function getAcmeApi(domainObject) {
     // we simply update the account with the latest email we have each time when getting letsencrypt certs
     // https://github.com/ietf-wg-acme/acme/issues/30
     const [error, owner] = await safe(users.getOwner());
-    apiOptions.email = error ? 'webmaster@cloudron.io' : owner.email; // can error if not activated yet
+    apiOptions.email = (error || !owner) ? 'webmaster@cloudron.io' : owner.email; // can error if not activated yet
 
     const accountKeyPem = await blobs.get(blobs.ACME_ACCOUNT_KEY);
     if (!accountKeyPem) throw new BoxError(BoxError.NOT_FOUND, 'acme account key not found');