iCloud.com 'connection error'

So, I'm on Safari, trying to sign into iCloud.com.

I use the right email and password (and I made sure to check this so I signed into appleid just to make sure)

I have the popup (on my iPhone, iMac and iPad as well as my MacBook that I'm using to sign in) asking me if I'm trying to sign to a new browser, so I click yes and put in the code (every single time, it's been about 10 times so far)

I get 'trust this browser' (every single time)

Then every time I get this: 'Cannot connect: iCloud encountered an error while trying to connect to the server'

So I've been 'sending the report to Apple' every time I get this error.

I'm trying to get to my iCloud Photo album - all my devices are reading different numbers (yes they're all hooked up to the same Apple ID, yes 'iCloud Photo Library' is on, 'Upload my Photo Stream' is on, 'iCloud photo sharing is on' on everything, so I'm trying to log into iCloud through Safari to find out exactly what photos are on that.

For clarification - this isn't the problem - the problem is not being able to sign into icloud.com - but the reason that I want to log on is this:

iPad - 245,391 photos, 2,495 videos, 1 item

iPhone - 292,315 photos, 2,872 videos, 1 item

iMac - 263,764 photos, 2,779 videos, 1 item

MacBook - 263,764, 2,779 videos, 1 item

So both Mac's are reading the same, but my iPad is less and my iPhone is more, so I want to log into iCloud to see exactly what that's got on it. Understandably I don't particularly want to have to sign out of iCloud everywhere because I store all my documents & everything on iCloud, I have the 2TB plan and 1/4 of a million photos!

I've restarted the MacBook, tried to sign in through a 'private' Safari window and nothing's working. I've checked the status and icloud.com is green so there isn't a problem with Apple. I've restarted the iPad Pro 10.5" (2 button press until the Apple symbol appears) and restarted my iPhone 7 Plus (2 button press until the Apple symbol appears), but I still see different figures for each device. I need to be able to log into icloud.com to see exactly what photos I have on the 'Photos' tab so that I know exactly which ones, if any, are right.

I have no idea how to access it. I only have one user on the MacBook, and only one iCloud account, am I missing something? I have 2-factor authentication on, so I tried using an App Specific password, and that tells me that the password is wrong, (which it obviously is) so it can't be that. I'm running out of ideas!!