Shell Card Portal link

Apparently it is possible to integrate the shell Card Portal with MYOB. I have followed the instructions by clicking on the link in the portal on multiple occasions and I always get nothing except an error message in the browser window as follows 

https://shellcardportal.shell.com.au/api/invoice-integration/myob-callback?error=invalid_state&error_description=The+state+is+missing+or+does+not+have+enough+characters+and+is+therefore+considered+too+weak.+Request+parameter+%27state%27+must+be+at+least+be+8+characters+long+to+ensure+sufficient+entropy.&state=2291038

I have raised the issue with Viva Energy "help" but they haven't given me any other response that "are you still having a problem?" three weeks later and I haven't had a response to my reply of "yes".

Has anyone else managed to overcome this issue?