ATT Yahoo Email login fails ERR_CONNECTION_CLOSED
I cannot access my AT&T Yahoo email account. My browser says the account needs to be re-activated by signing in, but trying to sign in puts me into a failure loop with the error message ERR_CONNECTION_CLOSED after I enter my email address. My browser says "It looks like oidc.idp.clogin.att.com closed the connection". Now the same is happening on my mobile phone, so I no longer have email. HELP!