fixes, in sequence

It won't open. Here is the order.

Nine out of ten "the market will not open" reports are not the market. The order below goes from the most common cause to the rarest. Work it top to bottom. Do not skip ahead, because the fix for the common case is the one that solves the rare case too, and skipping it means fixing the wrong thing twice.

Read the error first

Symptom	What it means	Fix
The "can't be reached" error, or a blank page with an error	Either the address is not being served, or the circuit died	Try the next one of the three addresses on the links page
The DDoS page does not pass	Congestion in the circuit, or scripts turned off	One reload. If it still hangs, drop the security level to Standard for the moment
The check screen spins past 60 seconds	A bad circuit	The onion icon in the address bar, then New circuit, then reload
No onion opens, even check.torproject.org	The problem is in Tor, not in the market	Bridges, below
Everything loads, but slowly	Normal for Tor. The first request is always the slowest	Wait. Do not reload

The circuit routine

1. New circuitThe onion icon in the address bar, then New circuit. The page reloads on a new route. This is the fix for the stuck check screen and most of the "can't be reached" cases. It changes the route, not the destination.
2. New identityThe harder reset. Use it when a specific circuit feels like it is the one following you, which is rare. It flushes more than a new circuit does, and it takes longer.
3. After a network changeMoved, switched from wifi to a phone, changed networks. Give Tor a minute to build a fresh circuit before you test the address. Testing on the old circuit tells you about the old circuit, not the new one.

Blocked networks

Some networks block Tor outright, and the symptom is that nothing onion shaped will resolve, not just the market. The fix is a bridge. Configure, then Network Settings, then Use a bridge, and paste a bridge line from bridges.torproject.org. Bridges are the way Tor gets through a network that has decided to keep it out.

The fast diagnosis: the same Tor Browser over a phone hotspot. If it opens there and not on the local network, the problem is the network, not the address. A corporate wifi, a guest mode on a router, a school, an office. The hotspot test takes thirty seconds and rules out half the remaining cases.

All three addresses refuse at once

Rare, and almost always it is the market. A flood, maintenance, pressure on the node. The fastest word on that is the Dread thread, where the market posts when it is down and the community posts when it notices. In this case the fix is time, not settings. Nothing on your side changes what is happening on the node's side.

Do not type your PIN into some "new" address that someone suggested in a direct message. The market does not move by word of mouth in a chat. It moves by a new string on the links page, and the rest are people who want your PIN while the real thing is down.

The links page has the three current addresses. The get Tor page covers the browser setup, including the security slider. The first visit page covers what the correct load looks like, so you can tell a real hang from a wrong page.