Recently my Skype For Business SSL certificate expired. I am assigning all SSL certificate one by one using internal CA server. When I'm trying to assign certificate to Front End Server, OAuthTokenIssuer it was not done with an error message "Server is in single user mode. Only one administrator can connect at this time.
I Tried to connect SQL DB. I was unable to connect and I changed the DB login password and accessed the DB. I couldn't find where to change the password at Front end server.