
Hi Lori,
Thank you for reaching out to Microsoft Community Support.
According to your issue, you have performed many troubleshooting steps including re-installation, but it did not work as well. As this issue has been raised multiple times but the majority of them has not fixed the issue except for this thread: users on IPhone or Android not being able to sign in - Microsoft Community.
Based on this, please help me to provide this article later to your IT teams and follow this direction to see if it works.
- Go to the SharePoint site where you used to sign in and work on it.
- Look at the top right > click on Setting (gear icon) > Site permissions
- On the permission page > click on Site Collection Administrators > add you to the Site Collection Administrators > click OK.
- You could wait 15-30 minutes then try to use your SharePoint app on your iPhone again.
Please send the first 3 steps to your IT team and try them to see if it works.
In the meantime, since you mentioned that you rely on SharePoint daily and do not carry your iPad, here’s a temporary workaround to access SharePoint from your iPhone:
- Open Safari (or any browser) on your iPhone.
- Go to https://www.office.com.
- Tap the three dots (•••) at the bottom right of the browser and select “Request Desktop Site.”
- Once the desktop version loads, tap the nine-dot app launcher in the top left corner.
- Select SharePoint from the list of available services.
This will allow you to access SharePoint through your browser for the time being.
Sincerely,
Austin H - MSFT | Microsoft Community Support Specialist