Unauthorized email addresses added to my account

Yes, change it several times. Also new emails are not highlighted.

I delete the ones that show up.

@user_7ikevp​ 

I delete the ones that show up.

Are you perhaps referring to email addresses that show up in your address book because of spam?

No, when I go to settings - accounts, I found unknown email addresses and delete them. Haven't got any new ones for the past week.

I sign in to my comcast email account, click on ID and Security. Along with my email address under 'comcast email' is another email address @ outlool.com under 'personal email'. That is the one I would like to delete but no provision to do so. Don't know how it got there and don't know how to get rid of it. However, I did have this address in my email under settings. account and was able to delete it there.

Tried changing it to another email address. Each time I get a message 'linked to an active account'. Tried several addresses, same message. 

I can set up another email address, but how do I get xxxx@outlook.com to link? I left click on the address in my account and get 'open link to new tab', 'open link to new window', 'open link to private window', save link as'.  Is this how I would be able to link it? And how would it confirm the account. Don't understand why I just can't delete it, if I am suppose to be able to maintain it.