Yes, after entering the credentials into the Laserfiche Web Client Config you must browse to the web server program files, Laserfiche Web Client folder and search for the web.config file. Add an irrelevant character anywhere in the file (like a space at the end of a line), then save it. Then go into the user config and try again.

Ege, 

Are you using a demo DocuSign Account, or a production account? I typically see this error using our internal demo DocuSign account when one of the following are true:

• The endpoints aren't set to demo.docusign.com in web.config (under web files directory)
• The integrators key wasn't added to the DS config  node in WebAccessConfig.xml (under web files\config directory). 

The 2nd one is easy enough to check and correct. For the first one, open web.config, ctrl+F for 'demo'. It will take you to a commented out line right above the two endpoint addresses you need to edit. Simply changes the two endpoint addresses from www.docusign.net to demo.docusign.net.

Chad's solution is interesting. I can't think of how such an edit to the web.config could directly fix an issue like this, but its possible it indirectly fixed it- saved edits to the web.config automatically recycle the app pool in asp.net applications, and its possible that restarting Web Client's app pool fixed some other problem and restored it to a clean state. In general, I'd advise being very careful about miscellaneous edits to web.config, as a stray character could potentially take down the Web Client. A repair would likely fix the situation, but back up the web.config just in case. 

Thanks Ryan. My WebAccessConfig.xml file had two DocuSignSettings blocks for some reason. The first one was already in the file when I started editing it, but it was located towards the middle somewhere so I didn't see it. I don't know where it came from. The credentials were encrypted so it definitely wasn't me. 

Anyway I removed that block and everything works now.