Fixes for the common problems.
Most Nexus problems have simple causes.
Almost always your Tor circuit or a temporary flood, not the market. Request a new circuit and retry, or switch to another address on this page. If all three stall across circuits for several minutes, wait a short while, because floods pass.
Stop. That is the phishing signal. Do not type anything, close the tab, and copy a verified address fresh. If a deposit has not shown, it is usually waiting on confirmations, or an underpaid Bitcoin fee, and you sent to the address from the correct order.