Hi,
Based on your description, you created an Outlook account six months ago, and you tried to create an Outlook account with the same email again. Correct me if I am wrong. This error will appear since you have already created an account with the same email address. If you have deleted the account, it cannot be reused to create a new account.
If you tried to log in, it will say it does not exist since it was deleted. If you tried to reuse it, it will not be allowed to be reused. Microsoft doesn't recycle/reuse its email address due to privacy concerns. You will get an error that of email address is already in use.
If you require further assistance, please don't hesitate to let me know.
Stay Safe!