When validating the target or source environment by mailbox to Office 365 the Autodiscover Validation fails with the following error in the webpage.
The Autodiscover service response was invalid.
This can be caused by a response that is not expected by the AutoDiscoverListener.
A clip from the WebService.log file.
Here the AutoDiscoverListener is connecting to Office 365:
AutoDiscoverListener - Request to http://autodiscover.outlook.com/autodiscover/autodiscover.svc returned redirection to http://10.61.61.170:81/cgi/warn.cgi?IP=10.61.61.35&CAT=WEMAIL&USER=OYA_CENTRAL\DEFAULT\adaalmberv&CE=0&URL=http://autodiscover.outlook.com/autodiscover/autodiscover.svc
The error line is below:
AutoDiscoverListener - <log42net.Error>Exception during StringFormat: Input string was not in a correct format. <format><html>
Further down in the log under the //---> line will be the response that was received to the AutoDiscoverListener.
It will be in HTML format but there will be text explaining what the response is. In this case it's below:
<p><font color="#000000" class="blockcopy">The website you are attempting to visit may violate your Acceptable Use Policy. You can click continue to visit the site or click cancel to not access the requested site. All Internet traffic is logged and reported.</font>
The autodiscover validation is trying to connect to Office 365 but because the response from the security appliance blocking the traffic, the reply is in not in the format it was expecting.
