public tcp forwarding without spending money

[Sucrose]

is it possible to forward port other than 80 or 443 on serveo without upgrading?

In https://serveo.net/docs/ it says to register before the command

ssh -R 1492:localhost:1492 serveo.net 

i've done all including ssh-keygen and submitting in the console of serveo. in other word, i've done registration.

i also get respond like "Forwarding TCP connections from serveousercontent.com:<port>"

but when i open the link, it always fails.

is there anything wrong? don't advise to upgrade in first place. it's expensive.