Auth exception: Refresh token has expired

Everything was working fine and It started throwing following error after I made a mistake. I have passed wrong appKey onetime. But not working after reverting back.

Auth exception: Refresh token has expired

Exception: Invalid resource owner credentials

SDK HTTP Error at https://platform.ringcentral.com/restapi/oauth/token

Response text: {

"error" : "invalid_grant",

"error_description" : "Invalid resource owner credentials",

"errors" : [ {

"errorCode" : "OAU-140",

"message" : "Invalid resource owner credentials"

} ]

}