why are photos not uploading to icloud?

I have My Photo Stream turned on, but for the last 2 weeks, photos I've taken on my iPhone are not showing up on my wife's even though we share an iCloud account. Up until 2 weeks ago everything was working fine.

The one change I've recently made is adding a new email account (work Outlook) to my phone. Would that have disabled the automatic upload to iCloud somehow? And if so, how can I change that?