if you can not do the trade or open up the exchanger site which mean your IP address had been blocked by them,
lately they're attacked by people and because of that the site has been down and it's very slow a few days ago,
they're tracking the IP of the attacker and blocking it in order to prevent another attack in the future.
so,your IP address suspected as one of the attacker that is why you can not reach their website,
other than that a new registration also disabled for now.
the only way to reach their site is by sending the ticket to them and proof it that you're not one of those attacker,
you can reach their website if they lift the ban in your account if not,say goodbye
i can easly change ip, did not worked, here the response from nova
Hi Sir
We are conducting some technical updates and that might be the reason for that.
We have no estimated time but everything shall be alright in the next working days.
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Regards,
NovaExchange support team