Hello Jorge,
I would run a SAP Logon trace :
Open SAP Logon -> SAP Logon Options -> Traces -> SAP Logon traces.
Click "delete all trace files".
Then activate the trace with all modes. (errors, warning,....etc)
Replicate issue and look at the traces errors.
If you cannot sort it out yourself, you need to open a ticket in BC-FES-GUI.
kind regards,
Eric Van de Catsije