Hi Lock,
Need few more details to understand your issue in depth.
- BO Version and Patch..?
- Connectivity type in Dashboard (Through Add Query Browser or QAAWS)..?
Generally, this issue will happen when you use SAP SSO connection in UDT. Every time this connection needs a refresh at universe level, cause UDT can't keep credentials in cache for long time. This leads following errors like "SI_LOCALE" or "Incomplete Logon Data" etc. To UDT trust and to keep your credentials for a long while we need to do "SNC" settings configuration at Back end, reach your basis team to do this (Not sure this would be a permanent solution for your issue), Other wise go with Pre-defined connection with Generic ID if you don't have any restrictions with Data.
Alternatively, if you are with BO FP3 then you can create an OLAP connection in IDT with SAP SSO then can use in Dashboard. As IDT is STS enabled so you won't get this kind of errors as per my knowledge.
Ref Notes: 1500150, 1747311,1635878,
Thanks,
Raju