As part of an ongoing Exchange 2010 to 2016 migration, I had to replace the self-signed certificate with a certificate from the customers PKI. Everything went fine, the customer had a suitable template, we’ve added the necessary hostnames and bound IIS and SMTP to the certificate. The mess started with an iisreset /noforce… Bild von Oskars Zvejs auf Pixabay The iisreset took longer than expected. After that, I tried to login into the ECP, entered username and password and got an error.