How do I force photo stream sync

Try going to iCloud.com using a computer to see if the items are there and whether they are from the device or the computer. That should show whether the device or the computer isn't syncing. If the computer, try going to System Preferences/iCloud and stop syncing. Wait a couple of minutes, then recheck syncing. If the device, go to Settings/Your Name/iCloud and do the above. You can also try signing out of iCloud and then sign in again.

Thanks. When I went to the computer(Mac) there was no sync button but it said iCloud drive where I click and it was empty.

On my iPhone no sync but "iCloud photo library & upload to my photo stream" which both were on.

Do you have other problems when trying to access the Internet?

Troubleshooting Wi-Fi issues in IOS

Does it not sync between the two Macs, or do photos from your mobile devices not appear?

Your iPhone will only stream new photos after you close the Camera.app, make sure it is charged, and it is connected to Wi-Fi.

If My Photo Stream is not updating between the Macs, there may be a photo in the Photo Stream that cannot be processed.

Try stopping the iCloud sync, wait a minute, and then reenable it.

All that said, the photos are suddenly showing up on my Mac after putting the iPhone on wifi, so maybe only iOS devices can see photos that were uploaded with LTE? Makes no sense!?

I don't know how your iPad is seeing the iPhone photos, but your Mac will only see the the photos after you connect the iPhone to Wi-Fi.The Wif-Fi connection is required to upload to iCloud, see this link: https://support.apple.com/en-us/HT201317

When do my photos upload to My Photo Stream?

Photos that you take on your iPhone, iPad, or iPod touch will automatically upload to My Photo Stream when you leave the Camera app and connect to Wi-Fi.

I've been traveling away from home for 4 weeks and my iCloud will not sync from any wifi. This is occurring on my two iphones.

I'd really like to force a sync.

my wifi is on and still not uploading photos to mac desk top

Did you check iCloud.com/Photos?

Thanks. I didn't need to go to iCloud.com/Photos bc miraculously my photos appeared. If this happens again I will remember to go to iCloud.com/photos'