Bad parameter error when signing PDF document

[Colin5C6C]

I have a client who is getting a bad parameter error when trying to use their digital signature. I have tried uninstalling/reinstalling Acrobat and also tried creating a new signature. 

Please advise, thank you. 

[Amal.]

Hi Colin

Hope you are doing well and sorry to hear that.

- Is this a issue with a particular PDF file or with all the PDF that he wants to sign?

- Would you mind sharing the steps the client is doing to sign the PDF?

- Also what is the version of the Adobe Acrobat DC he is using? To check the version go to Help > About Acrobat and make sure you have the latest version installed. Go to Help > Check for updates and reboot the computer.

Please try the following steps and see if that helps

1. Launch Adobe Acrobat DC
2. Select Edit -> Preferences...
3. Select "Signatures" from Categories
4. Click "More..." button on Creation & Appearance block
5. Uncheck "Use modern user interface for signing and Digital ID configuration"
6. Click the "OK" button and then again click "OK" button on Preference dialog

If it doesn't work try to click the "Certificates" button, then Certify Visible Signature, then draw a new box in the field you want signed and see if that works.

Regards

Amal