I have the same problem on mac. Watched a movie yesterday, no problem. Went to watch the F1 today, won't work. Says error and I'm using too many devices. I only use my mac and iphone. Reinstalled it, deleted cookies, still won't work. Looked in my account and it only lists mac, iphone and roku (whatever that is). Any ideas anyone?
Yes, the limit is 3 devices at once.
And you can now have as many devices as you like set up, though a maximum of six are shown on your Now dashboard, and only those of this six which support downloads can have downloads on them.
Using a device outside of this six will work, as long as it doesn’t break the simultaneous devices limit, and it will be seamlessly swapped into the six you have, knocking out the device last used longest ago which has no downloads on it. Or, if they all have downloads, the one last used longest ago.
This has replaced the clunky old system where you could only have three device swaps a month, and if you wanted to use a seventh device, you had to go in to your account and delete one of the six.
The new approach isn’t perfect yet; you can’t delete devices for yourself, so a lot of devices are still in member’s lists, even though they own them any more, and you can’t rename devices for yourself, so you can get a maze of twisty little Now devices, all the same, which you can’t tell apart.
But we may yet see these issues fixed.