Avalara plugin not getting activated

My avalara tax plugin account Id and license keys are not getting activated in live site, but when i do it in the local i get the response from avalara API. what might be the issue for this.

Are you getting any specific error on the configuration page or in the log (admin area > system > log)?

Tax.Avalara error. AuthenticationException - Authentication failed.
Details: Missing authentication or unable to authenticate the user or the account.

This is 3.70, what i did was tried to upgrade it to 4.60 by pointing my site to the D drive folder but for some reason the site did not work as expected. after this i reverted the site to point the 3.70 version which is in C drive. after this change i get this error and cart takes atleast 1 minute to load. i am not sure if the "OverriddenShoppingCart" controller was customised please advise

This i get in the 4.60 version but in 3.70 i dont get any specific error in the log.

Tax.Avalara error. AuthenticationException - Authentication failed.
Details: Missing authentication or unable to authenticate the user or the account.
This i get in the 4.60 version but in 3.70 i dont get any specific error in the log.

what i did was tried to upgrade it to 4.60 by pointing my site to the D drive folder but for some reason the site did not work as expected. after this i reverted the site to point the 3.70 version which is in C drive. after this change i get this error and cart takes atleast 1 minute to load