Portable Add_Account Error (unknown encoding: ascii)

Have just updated to 1.2.15 from 1.2.4 and wanted to add an account using the headless Authentication method.
No matter what I try I get the error "Error: unknown encoding: ascii"
I have tried a different Google account with no improvement.
Was working fine on 1.2.4 not sure what has changed that could cause this issue.
I’m running Insync on DSM 5.2. (Busybox Linux).

@Piper_Green Is your locale set to a UTF-8 one? You can check this by running “locale” in a terminal. If not please try setting it to one then restart Insync. Let us know how it goes.