Issue setting up charter.net and iCloud email accounts on MacBook Air

Are you trying to add these email accounts to the Apple Mail app on your MacBook Air, or trying to access them via a web browser on the same Mac?

If it is for the former, I suggest that you start with your iCloud email account, and then, onto your Charter account.

For iCloud

1. First verify that you can successfully access your Apple Account at this website: One account for everything Apple
2. If successful, then I suggest that you sign out of your Apple Account on your Mac, and then, sign back in. Ref: Sign in to or out of your Apple Account on Mac - Apple Support
3. If successful, let's add your iCloud email account to the Apple Mail app. I am assuming that you currently do not have this account added to the app. To make sure you didn't miss a step, use this Apple Support article to add your iCloud account: Add email accounts in Mail on Mac - Apple Support

For Charter (aka, Spectrum)

AFAIK, Charter/Spectrum will no longer allow using third-party (in this case the Apple Mail app) apps to access their email service. Ref: Charter email still not working with apple mail. Any suggestions? You will then be required to use a web browser instead.

However, the following is what is typically used if you still want to try adding it to the Mail app. Since Charter/Spectrum is not listed, you will need to use the "Custom" option and fill in the requred fields with the following:

Incoming Mail (IMAP)

• Server: mobile.charter.net
• Port: 993
• Security: SSL/TLS
• Username: Your full Charter (or Spectrum) email (e.g., `you@charter.net`)
• Password: The one you use to log into your email

Outgoing Mail (SMTP)

• Server: mobile.charter.net
• Port: 587
• Security: SSL/TLS or STARTTLS
• Requires Authentication: Yes (use same credentials as incoming)

What you’re seeing makes sense, but I can see why it feels like an endless loop. On Apple’s side, your iCloud email address isn’t technically its own separate account — it’s considered an alias (or sometimes the “primary email”) of your Apple Account. That’s why in System Settings → Internet Accounts, macOS shows it tied to “iCloud” rather than letting you add it again as a standalone mail account. Essentially, macOS is preventing you from duplicating the same credentials twice.

Since it works on your iPhone and iPad, the good news is your Apple Account and iCloud Mail itself are healthy. The loop happens because Mail on the Mac is expecting you to enable the “Mail” service from the existing iCloud account, not create a brand-new Internet Account. Here’s what usually fixes it:

1. Go to System Settings → Internet Accounts

2. Select your iCloud account (the one showing your alias).

3. In the list of toggles (Mail, Contacts, Calendars, etc.), make sure Mail is turned ON.

4. Then open the Mail app, and your iCloud inbox should appear automatically.

If you already tried that and it still loops, sometimes removing the iCloud account completely from Internet Accounts, rebooting, and re-adding it resolves the confusion. Just be sure you know your Apple Account password and have two-factor authentication handy before signing out, since it will sign you out of other iCloud services on the Mac as well.