Signing document with a certificate: Clicking on the Sign button does not work (no feedback)

[martim_0306]

Some Acrobat Reader Users in our company have reported that when they attempt to use a certificate to digitally sign a pdf document they experience the following behaviour:

>Click on Use a Certificate

>Click on Digitally sign

>Select the signature area

>They then select the valid internal signature Certificate

>Click on Continue

>Select the desired appearance

>Click on Sign and nothing happens. The "Sign as (Name)" Window stays open without any error message or feedback of any sort. 

We are very confident that this is not related to the certificate, since both renewing the certificates or doing the exact procedure from a different PC seems to "solve" the issue. 

[martim_0306]

Small correction: renewing the certificates on  does not solve the issue.