It seems the EST server is rejecting connections.
curl https://testrfc7030.com:8443/.well-known/est/cacerts -o cacerts.p7 --cacert ./dstcax3.pem
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
curl: (7) Failed to connect to testrfc7030.com port 8443 after 171 ms: Connection refused