Icloud.com keeps logging me out on my Surface PRO

After logging into icloud.com to access email on my Surface PRO, the application automatically logs me out. Using any of the icloud features - email, calendar, photos, etc. Sometimes immediately, sometimes after a few minutes. Very inconsistent has been occurring for 4 days. Apple support had no answer. I have verified storage, system updates, and virus scan. Attempted to use different browsers (Google, Edge) - same issue experience. Attempted to download and install icloud app from microsoft store - same issue experienced. Issue does not occur on my iphone. Any suggestions...anyone else experiencing this annoyance? Prefer not to work from phone 100%.