GoogleCalendar auth request gave code as '4%2Fvg*************'. which will results into malformed_code

Whenever I am connecting my two or more google accounts and trying to generate auth code, its giving an auth code in format '4%2FvgE2QZXT8S2KhAqln2*****' while in normal case it is '4/vgE2QZXT8S2KhAqln2*****'. and this '4%2FvgE2QZXT8S2KhAqln2*****' auth code gave an error while access token generation.....

{ "error": "invalid_grant", "error_description": "Malformed auth code." }