Thank you for reporting the issue.
First, i hope you have restarted your machine after the update.
Second, please uninstall Reader and try installing again. I am sharing with you a different version of Reader so that we can be sure that the previous one has not gone into a corrupt state.
Please install from ftp://ftp.adobe.com/pub/adobe/reader/win/Acrobat2015/1500630033/
Then go to Help -> Check for Updates. This will install the latest version for you.
In case, you still face the issue after doing so, please send us a screenshot of the exact error message.
Thanks and regards,
The file I access through the link is an exe file. I am not working with Windows but from a Mac Book Pro. So, I assume I would need a different download link.
The issue continues. The file seems to be older than the most recent reader DC file that I had installed and deleted to allow for this new installation. The error message continues to appear and this time the certificate shown before the error message is an old certificate that will expire in July 2017, while I have a new certificate (change of lawyer ID where the certificate is included) expiring in two years. This means that an older version opens an older certificate.
Can I retrieve solely the adobe reader Dc version prior to April 5, 2017 (when problems started) from my Time Machine?
Since the issue persists in older DC version also, I do not think the issue is caused by any Adobe update.
Maybe there is some issue with the Mac Sierra update. In home we cannot reproduce the issue.
Please send us a screenshot of the error message that you get.
Also please select the digital id for signing in Acrobat-->Click on "View Details" link beside the id -->Click on "Summary" tab and take a screenshot-->Click on "Details" tab take a screenshot -->Click on "Revocation" tab and take a screenshot
Please send all the screenshot details and mail to email@example.com. We will need all these details to analyze the issue.
Thanks and regards,