Might be something with your browser / cookies themself, then if not on the same PC as the Wifey?
Test a second browser - always.
If it still won’t work for you, it is something with the PC or them, like you’re thinking:
For your side...
If different PCs than what works for the Wife - after testing on her PC that you’re able to login fine - hold your CTRL key down when on their page and while doing so, tap your F5 key. It will force a refresh of the page from the online version if your browser is somehow stuck thinking it should use a cached copy of the page that no longer works.
If all else fails, do the usual(knowing it will require you to retyoe all those pesky PWs in again, and delete your cache/cookies/etc. from your browser.
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If still not able to connect on a totally separate and second PC, you can say it is them with your particular account. A last test could be making a new dummy account and see if it works AOK.