ROS 7.12.1 - enable-ssl-certificate with UserManager

Hi,

I am trying to renew LE cert with enable-ssl-certificate but I get the following error.

/certificate/enable-ssl-certificate dns-name=somegw.of.mine.com
  progress: [error] http challenge validation failed, please make sure www service is enabled and your device is accessible by letsencrypt.org servers

Yes I have enabled www service and firewall filter rule (also not NAT rule).

I have installed UserManager.
This is the only difference and ROS (7.10.x) version when I first created the cert with no problem.

Can someone try to recreate the cert?

http://forum.mikrotik.com/t/lets-encrypt-certificate-automatic-renewal-in-ros-v7/165090/4