Can't access the remote assistant externally

very new to HA so might be something I’m doing wrong.
I’ve set up HA on a virtual machine on Unix. I’m able to access it from my local network.
I’ve set up a No-IP account and opened have my TP-Link router update it regularly.
I’ve created, in my TP-Link router, a virtual server to forward port 8123 to the VM IP - for starter it is not secured (will take care of that afterwards).
When I try access the HA from external network I get “server take too long to respond” which, to me, means there is no blockage from my router but rather from the server. I’ve also looked at the HA and saw that “external access is disabled”.
What am I doing wrong here?