Do you means that you cannot login Exchange on-premises admin center?
If so, I would suggest you try to login with "https://localhost/ecp" on your Exchange server. Check whether could login with the URL successfully.
If you cannot login ECP with this URL, try to open IIS and recycle ECP (MSExchangeECPAppPool) and OWA (MSExchangeOWAAppPool) Application Pool. Then try to login again.