Hi man ky,
Thanks for reaching out to Microsoft Q&A.
Please try below steps:
- If you're using mobile data, try switching to Wi-Fi and vice-versa. Make sure Airplane mode is off.
- Make sure you're using the latest version of Authenticator - Microsoft does not support any app versions more than 12 months old. Tap Settings and make sure App updates is turned on. Get the latest.
- Tap Settings and select Turn off battery optimization for better sync performance.
- Tap Settings > Notification Settings and make sure Show notifications is turned on.
- Make sure your device is up to date, and that any other security apps (such as Microsoft Defender and Intune Company Portal) are also up to date. Make sure the device's Date & time are correct too.
- If you're using VPN, try disconnecting to see if the issue persists.
You can also remove your account and attempt the sign in again. If you are still not able to add your account, please contact Support or reach out to your IT admin.
Please do not forget to "Accept the answer” and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.