Photos stopped updating to icloud, can't access icloud

Hi there, I hope you are all well.

Okay let me try and get all the important information out there

I have a Mac Mini

OS Monterey 12.7.6

Late 2014

On 7th September the photos on the mac stopped syncing with icloud.

I have a message today saying Uploading 87 items which I presume has been running for weeks now. If I try to pause the message nothing happens.

I have an iphone 13 Pro Max running iOS 26.1

I have an Ipad Air 4th Generation running iOS 26.01

I take a considerable amount of photos with my iphone and ipad for work which I then process on my mac.

Now it appears that the photos are still syncing between the iphone and the ipad without any issue.

When I tried to login to www.icloud.com on my mac, I reach a check page that says your email must be verified - however - when I try to provide the information requested I get an

An unknown error has occurred

So I'm unable to log into icloud through a web browser on any device.

Anyone experienced this, or able to explain how I resolve this?

Thanks for any help.