My network environment has ISA and exchange server 2010, when I use a new certificate in my ISA and exchange CAS server and when I navigate to the OWA page form our client machine, we can get to the login page but after logging in we get an error page with the following message "Error Code: 500 Internal Server Error.  The signature of the certificate cannot be verified. (-2146869244)".

Please help me ASAP. Your cooperation will be highly appreciated.

Thanks

Rana

Hi Rana Babu,

How and from where did you issue this certificate.

512 bit keys have been blocked for a while now. This update will block the use of cryptographic keys that are less than 1024 bits.

Check yours:

Open the certificate
Details Tab-> Public Key -  RSA(2048 Bits)  - should be visible similar to this.

You can run the following query on your Certification Authorities (CAs) in order to discover certificate templates that are utilizing
keys under 1024 bits:

Certutil -dstemplate | findstr "[ msPKI-Minimal-Key-Size"| findstr /v "1024 2048 4096"

Note: The command should be run in each forest in your organization.

References:

RSA keys under 1024 bits are blocked

The signature of the certificate cannot be verified 0x80096004 (-2146869244)

Hi Babu,

Have you tried the suggestion above ? How about the result?

Best regards,

Hi Satyajit, 

I have used it in my ISA and Exchange CAS server, when if I use this new certificate only in my ISA server it work fine but if I use this certificate in both ISA and Exchange CAS server it create the below problem: 

"Error Code: 500 Internal Server Error.  The signature of the certificate cannot be verified. (-2146869244)"

for your kind information my new certificate key length is RSA (2048 Bits)

Thanks.