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It seems that you are experiencing issues logging into Azure Language Studio due to restrictions on using personal accounts. If your Azure subscription is linked to a work or school account, you will need to sign in using that account instead of a personal Microsoft Account (MSA).
If you are unable to recover your account and it states that the username is not found, it might indicate that you are trying to use the wrong email address associated with your Azure subscription. Make sure you are using the correct credentials that were used when setting up your Azure subscription. Please contact your resource admin if you add your email on the resource again.
Kindly refer below link: Visual Studio Subscription
For Reference thread: login into Azure Language studio
Thank You.