Unable to add Xero as a datasource

Hi, 

Unfortunately despite attempting different browsers and different Xero accounts we have been unable to add Xero as a datasource. 

We persistently receive the error message below.

Strangely we are (sometimes) able to succesfully create Xero as an "app" but from there we are unable to treat it as a datasource or to create any custom reports. 

Any help would be greatly appreciated,

Thanks