Hi SAP Basis,
Follow the sapnote 1476839 - PI SLD: Error accessing a remote SLD via RFC
Follow the steps:
1. Logon to the remote SLD with "http://<host>:<port>/sld"
2. Navigate to 'Administration --> Details --> Data Suppliers'
3. check whether the 'RFC server threads' are running.
Also check the 'Gateway Host' and 'Gateway Port' entries displayed there. Verify whether they are correct.
You can change 'Gateway Host' and 'Gateway Port' settings with 'Administration --> Settings --> Section datasupplier'.
Leave the fields empty to use the defaults. Restart the SLD after that.
With Regards
Ashutosh Chaturvedi