The MaxRequestBytes registry value, which is not present by default, determines the upper limit for the total size of the Request line and the headers. This value is typically set in tandem with a companion value, MaxFieldLength. The MaxFieldLength IIS registry parameter specifies the maximum size of any individual HTTP client request. In larger environments, if these values are not set to 32768, Microsoft Office Outlook® Web Access for Exchange Server users can experience logon failures. Specifically, the absence of these values can cause HTTP 400 - Bad Request errors. When configuring the MaxFieldLength registry value, you must also set the MaxRequestBytes parameter to 32768 to enable users who are members of more than 75 groups to log on to Outlook Web Access. If its value is lower than MaxFieldLength, the MaxFieldLength value is adjust