Unable to access routers configuration page remotely

I'm a new to networking please bear with me. I have configured an account on no-ip.com to access my cameras remotely. So after installing their Dynamic Update Client it gave me a public address/domain. Previously when I went went to that address I could see my router from any where and then enable UPnP and all was well. A few months later same windows computer same configurations give me different results.

     This site can’t be reached

     xxx.xxx.xxx.xxx took too long to respond.

Obviously ping is reporting a 100% packet loss.

I changed OS moved to Ubuntu just in case but I still have the same results. I need help here please. What could be going wrong? I'm thinking it might be my ISP but I'm not sure how to be certain of if. In case it's my ISP is there a way to bypass the blockage on entering coections to my router?