Greets:
Just for reference, it's WordPress Multiuser that you're running. Not wordpress. There is a difference.
We also need need a lot more information to go on. What's your server, which version of WordPress Multiuser are you running, is anything showing up in your error logs, etc.
Some other questions:
- What are you running for plugins?
- What's the load on the box?
- How do you have the domain setup on the box? Is it a regular hosting account or a addon domain?
- What else are you running on this box?
- What steps have you taken to resolve this issue already?
Any information you can give would help. Afraid you've give us nothing