Hello pitaspa,
Thanks for sending the details.
We will provide you with steps on how to add email (IMAP) to your Outlook app. Before that, we recommend you get the list of IMAP server settings for Charter emails handy (you may contact your email service provider about this).
To begin, let us create a new Outlook profile. If you can launch Outlook, go to File tab and select Account Settings. Under it there should be Manage Profiles. Choose Show Profiles and select Add. In the Profile Name box, type a name for the profile (Example: Outlook 7/20), and then choose OK. Source: Create an Outlook profile - Microsoft Support
Next is to set up IMAP email on Outlook profile. Select the Manual setup or additional server types and click Next.

Choose POP or IMAP in the service and select Next.

Next, provide the information especially the yellow on the box as this should match Charter email configuration.

Then, choose More Settings ... to get into Outgoing server and tick My outgoing server (SMTP) requires authentication.

Then, on Advanced tab, select SSL or else keep it as it is and enter the port numbers.

On the main page, select Next.
Followed by waiting of two green marks on the syncing method. This part will lead to an error if you will have to generate app password or else, please let us know the error message and code.
Should you see this, congratulations, you have successfully added your email to Outlook.

If you are back to this prompt, at the bottom, please select the Outlook7/20 on the Always use this profile. Select Apply and OK. Relaunch Outlook app and see if you still get the same error and update us in here.

We will wait for your response.
Regards,
Kathy A.