I think you have to turn on java in your firefox browser' you can refer the following link https://www.wikihow.com/Enable-Java-in-Firefox

You need to give more information on what you are referring to with digital signature so people can help you with that.

As for Java are you referring to Java Plugin from Oracle or to JavaScript built in Firefox as they are two different things. The only NPAPI Plugin that has been allowed to run in Firefox since Fx 52.0 Release has been the Flash Player Plugin from Adobe.

http://kb.mozillazine.org/JavaScript_is_not_Java

dear sir not resolve my problem as till date. and not helpful this link for ours. java not verity under this bowers. so that i am not able to use digital signature . so please provide me help asap....

As I said "The only NPAPI Plugin that has been allowed to run in Firefox since Fx 52.0 Release has been the Flash Player Plugin from Adobe."

So this includes the Java Plugin from Oracle not being allowed to run in Firefox since 52.0 to current including the Fx 71.0

Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work? https://support.mozilla.org/en-US/kb/npapi-plugins

Oracle has been in the process of depreciating their ever vulnerable Java Plugin for a long while now as only Java 8 even comes with it and IE may be the only web browser to still allow it to run now days.

Where/how are you using this digital signature ?

Can you attach a screenshot if you get an error message ?

• https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem
• use a compressed image type like PNG or JPG to save the screenshot