Hello Joice,
It might be connection problem.
If So please contact Basis guy to do connection test as well as Authorization test.
If not then might be the issue with RFC stuck up you need to goto OLAP source RFC batch monitor and manually execute all RFC jobs.
Or Possibility for IDoc stuck up.
To process Idoc manually Go to BD87.
Give your IDoc no in selection screen and then process manually.
Follow Siddhartha's steps.
Hope this will help you.
Thanks & Regards,
Maunank Patel.