Unity is not being made available to you due to trade restrictions:
Unity Technologies is listed and incorporated as a business in the
U.S. This means that as a company, we must abide by the legal
sanctions implemented by the U.S Government.
This means that some countries do not have access to the Unity sites.
Currently countries on this list include Iran, Cuba, Syria, Sudan and
Unfortunately, if you are a developer in any of the above countries
there is not anything that can be done regarding your access to Unity.
It is however, important to keep up to date with any changes that may
be made by the U.S Government in relation to these sanctions.
Next, there's the matter of the Unity Software Additional Terms:
7. Export Law.
You agree to comply fully with all export laws and regulations to ensure that neither the Unity Software nor any
technical data related thereto nor any direct product thereof are
exported or re-exported directly or indirectly in violation of, or
used for any purposes prohibited by, such laws and regulations.
Since your access is being restricted due to trade restrictions & they have disclosed the nature of the situation, my read is that your use of Unity would also violate their ToS, which means that you could be subject to the following from the Unity Terms of Service
7. Termination And Account Cancellation
Unity will have the right in its sole discretion, and without prior notice to you,
to suspend or
disable your Unity Account or terminate the Agreement and/or your
right or ability to access or use any of the Services if: (a) you
breach this Agreement; ...
As such, if you are using Unity when you are legally not permitted to do so, they can pull your account & products. They likely have some obligation to take action and that's a relatively easy solution for them to take which allows them to avoid some significant legal problems for being non-compliant.
There may be additional legal ramifications as well; for that you would need to consult with a lawyer. Ultimately, I can't tell you whether or not it's okay for you publish with Unity. All I can provide is my informed opinion & that is to do so would violate their terms of service and place your work in jeopardy. I wouldn't willing use such a strategy with my own work.