icloudiphonephotosstorage
My iPhone 11 says that 577 of my photos have not been uploaded to iCloud because there is not enough space.
However when I go to Settings > iCloud it says that I have only used 35.6 of 50 GB of the storage.
All of my other 1000 photos have uploaded but I don’t know why these are not.
This isn't referring to storage on iCloud but on your device itself.
Go to Settings > General > Usage
Under Storage (which is above iCloud) you will get a list of all the apps by size. If there is one you don't use you can delete it to get space to take a picture. If you don't see a list of apps, your phone is probably processing through and you will see a spinning indicator until it finishes:
Set "Upload to My Photo Stream" on in Photos and Camera Settings
Best Answer
If your iPhone storage itself is full, it can stop the ability to upload to iCloud.
Source: MacWorld