Photos uploading stuck on Paused

Hi, my Photos v 3.0 on iMac is stuck on Paused for a week now. Clicking on Resume does nothing.

iMac hard drive has 100GB free space.

On iCloud settings, every checkboxes are checked. I am on paid 2TB plan, 1.74TB free space.

Tried to turn iCloud photos on/off. Tried to turn iCloud Photo Library on/off. Nothing.

I have tried this for a week now.

Every day I click on this blue Resume link and nothing happens.