Hi @Keale
Welcome to our forum!
For better research, please provide more details about this case:
Do other users in your organization have the same problem?
Are you creating a new personal account?
What is your Outlook client version? Please make sure to update to the latest version.
Based on your description, it appears that an issue with the desktop client is preventing you from logging into your account.
I would like to know how you added the account failed, is there any error message? Please try to re-add it by following the steps in the following article: Add an email account to Outlook - Microsoft Support.
I have set some rules that cannot be used on a web browser. Are the web version and desktop client independent and not synchronized?
The rules for the desktop client and OWA are not all synchronized. There are two types of rules in the Outlook desktop client: server-based rules and client-only rules. For server-based rules, they are synchronized to the server side. For client-only rules, they don't.
Generally speaking, the inbox rules of the Outlook client have richer conditions and actions than the inbox rules of OWA, for some specific requirements, you need to use the client-only rules to implement them. More information, see: Manage email messages by using rules - Microsoft Support.
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