Using Classic Outlook on Windows for personal email, calendar, and contact management
This actually appears to be a current Spectrum problem, not something you necessarily need Microsoft to fix. I don't think it is the same as what you had in 2024.
Spectrum has a current known issue affecting Spectrum/Charter email accounts in desktop email programs. On August 23, 2026, a verified Spectrum employee confirmed. See this discussion: https://community.spectrum.net/discussion/179570/odd-problem-accessing-charter-net-email