Save settings problems

I have downloaded and installed WPDM (free) plugin and i tryed to configure, but:

1) in “update” tab i inser my credential to login and press save setting it goes on “working” but doesn´t save
2) I want configure reCAPTCHA : i insert the 2 parameters and “save settings”, but it goes on “working” but doesn´t save (i use the api key for another plugin and it works)
3) i want configure and use the “google drive addon”: i insert the Api and ID and save settings, but it goes on “working” but doesn´t save.

So 3 diferent situations but the same problem.

Ideas?

Nobody hat this problem?