From Microsoft's NT 4.0 knowledge base:
SYMPTOMS
Users on computers running Windows 95 report the following error:
This request is not accepted by the network. Try again later.
CAUSE
The user may be attempting to connect to a share that is configured to allows a specific number of connections, and that number of connections has been reached. Check the properties on the share on the server.
RESOLUTION
If the specified number of connections has been reached, increase the user limit or set the value to "maximum allowed."
MORE INFORMATION
There are several other parameters that you can check when troubleshooting a problem with limited connections to the computer.
Verify that the computer is running a retail version of Windows NT. To verify this, check the Licensing tool in Control Panel and make sure that the following message does not appear:
Not available in NFR (Not for Resale)/MSDN Edition of Windows NT Server.
The server may be configured with Per Server licensing and the number of licenses may be exhausted. A quick check to see if this is the problem would be turn off the License Logging Service on the computer.
Check to see if the server was configured by upgrading a computer running WindowsNT Workstation to Windows NT Server. If it was, the following registry parameter may need to be increased from a hex value of 0xa (10) to 0xFFFFFFFF:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanManServer \Parameters\Users
NOTE: The above registry key is one path; it has been wrapped for readability.
For additional information on changing this value, please see the following article in the Microsoft Knowledge Base:
ARTICLE-ID: Q122925
TITLE : Upgrading From Workstation to Server Limited to 10 Connections