unable to connect to my Mikrotik

Hello all,
so my ISP brought 2 routers, a Microtik which is on the roof, and a Tp-link in my room., he connected the TP-link to the MIkrotik through a cable.
I want to forward some ports on my MIkrotik but I am unable to connect to it, when I plug the cable in my computer it says “unidentified network”!
but the Mikrotik is working fine with my TP-link router, I have internet connection , but I am unable to connect to the MIkrotik directly,
do you have any idea how to fix this?
I tried with another computer, the same thing.

Note:when I ping the gateway I see a positive reply.

It is not broken, it is set so. Contact your isp to change the settings according to your needs. He will explain you how and why it is set so.