Problem to use Dropbox documents with Adobe Sign

I used Adobe Sign with my iPad Pro and it works for a long time. I can have a signature on Dropbox documents but it doesn't work anymore since feu weeks ago. I try to find Dropbox Documents by using Adobe Sign but I cannot find the documents. I have the feeling that the App take a very long time and nothing appears.

I tried to uninstall Adobe Sign on my iPad and to unlink Dropbox with the Adobe Sign App and nothing work.

Please, tell me how I can have my Dropbox documents downloaded in Adobe Sign App again.