Portal to SLD connection failes with Error while obtaining JCo Connection

Dear all,

We are running on NW04s EP7 SP09 and are intermittently getting this error message:

Error while sending HTTP data. Status: 401. Message: Unauthorized. Please check if the target SLD system is available and the SLD bridge is started there.

User Guest, IP address

HTTP request processing failed. HTTP error [401] will be returned. The error is [Authentication did not succeed.No details available].

which results in the error : Error while obtaining JCo connection....

The temporary fix is to unlock the "SLDDSUSER" account on the SLD server. I am not sure why this account gets locked?

Thanks, Neeta