I have somewhat of a workaround just from searching all around the web and gathered that it is editing the registry. I've tried these and it hasn't been consistent with all workstations, but has improved on quite a few:
Edit Registry setting to allow more connections
1. Start Registry Editor.
2. Locate the following key in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_MAXCONNECTIONSPERSERVER
3. On the Edit menu, point to New, click DWORD Value, and then add the following registry values:
Value name: iexplore.exe
Value data: 10
Base: Decimal
Value name: OUTLOOK.exe
Value data: 10
Base: Decimal
Note: set this value to the connection limit that you want for HTTP 1.1 connections. By setting the value to 10, you increase the connection limit to 10.
4. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_MAXCONNECTIONSPER1_0SERVER
5. On the Edit menu, point to New, click DWORD Value, and then add the following registry values:
Value name: iexplore.exe
Value data: 10
Base: Decimal
Value name: OUTLOOK.exe
Value data: 10
Base: Decimal
Note: set this value to the connection limit that you want for HTTP 1.1 connections. By setting the value to 10, you increase the connection limit to 10.
6. Exit Registry Editor.
7. Restart Computer.
Other Registry Settings to adjust:
1. Implement MaxUserPort registry to help the client computer regulate the amount of available connection ports that the client can use at any given time.
a. Click Start | Run | regedit
b. Locate and then click the following subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
c. On the Edit menu, point to New , click DWORD Value , and then type MaxUserPort .
d. Double-click MaxUserPort , and then set a decimal value to 65534.
2. Implement TcpTimedWaitDelay which helps the system to moderate the port usage of Windows.
a. Click Start | Run | regedit
b. Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters
c. Click Edit | New | DWORD Value | TcpTimedWaitDelay
d. Double-click TcpTimedWaitDelay , and then set a decimal value of 30.
e. Exit Registry Editor.