Using classic Outlook for Windows in business environments
I am having the same problem. Outlook suddenly cannot connect to my Spectrum email account. I have talked to Spectrum email support on the phone, and after helping me check things on their end (I can login directly to my Spectrum email account on their webmail through MS Edge), and then deleting and re-adding my Outlook account they said it is a problem with Outlook and to contact Microsoft support. But in attempting to contact MS Support on the phone all I get is automated answers to go online where there are threads like this with everyone saying Outlook suddenly doesn't work with Spectrum email anymore.
I have had this happen once before, and it took an Outlook update from Microsoft to fix it.
Please look into this, Microsoft. Something has gone wrong with Outlook's ability to connect with Spectrum email.