If you are experiencing this issue with Windows 10 Technical Preview the first step towards resolving the problem is to ensure that your network adapters are up-to-date with the latest drivers released by the manufacturer. If the drivers are older, or if they were upgraded from a prior version of Windows, updating the drivers will likely solve your issue.
Other potential causes could include third party security solutions, which have been reported by some users to conflict with Windows 10. If you have a third party security software installed, I would disable it temporarily to see if it affects the situation. If you continue to have issues, you should provide the hardware and software specifications of your system to allow us further...