Nighthawk RAX45 iCloud stopped syncing

Howdy: I bought the Costco specail, Nighthawk RAX45    .  Overall good router.  I see an markable improvement compared to the R6100.

Nonetheless, now my iCloud (Windows 10) is no longer syncing.  This happened when moving to the RAX45.

I have tried support with Apple and have yet to find a solution.

Before I return the RAX45, has anyone else experienced a similar issue?

This has exhausted me, and I refuse to donate anymore of life trying to fix this problem.    iCloud has to work.

I hate to have to return the router to Costco, but the RAX45 is the weak-link here, but am I the only one experiencing this?

Thanks in advance.

Frank.