We are in coexistence with Exchange 2010 SP3 and Exchange 2013 CU3 while transitioning. We have two servers with CAS and two servers with multirole (CAS and Mailbox)
We are stuck in a situation where user when accessing options from OWA is presented a sign in page and is not able to enter the options. After some time it able to open the options though.
We noticed this when we tried to restrict the user to change his profie picture from Outlook where when the user clicks on the "change" link under his photo, he is taken to Outlook web app page which the user fails to get past.
We also verified loging into the OWA and ECP page and clicking options present the sign on page some time, when it does any attempt with correct password fails to work and the sign on page stays.
We also notice this behavior occurs for some time and after some time it works normal, i.e. clicking options opens the option page normally without presenting the sign on page which is very confusing.
Virtual directory authentication for ecp and OWA -
ECP -Anonymous authentication - Enbled and Basic authentication - Enabled
OWA - Anonymous authentication - Disabled and Basic authentication - Enabled
Both Internal and External client authentication method is set to ntlm