"Account Blocked" when attempting to sign into Community Forum.

We have 2 Xfinity accounts, each in a separate Town,  Account "L" and "H", both in long term good standing.

For Acct: "L" when attempting to sign into Community Forum, the immediate response is "Account Blocked" 

It's been like that for years, there was never a challenge to register, phone support is at a loss. Both accounts

otherwise function normally.  This post is coming from acct "H" where there's no issue.  Thank you for any 

direction to get this resolved.