Hosted Applications Client – 6.xx known issues

Version 6.xx of the Hosted Applications is entirely written in the Microsoft .net framework and represents a fairly major change to the underlying code of the connector.  The Microsoft .net code allows the client to be much smarter, adding functionality such as Secure User Credential validation that occurs before logging onto the platform.

Version 6.xx has been designed to use the same “Auto Update” software as previous versions of the Scomis Client.  The Scomis Lab environment which comprises of standalone Virtual Computers running in the Scomis Data Centre as well as in Microsoft Azure had all been used to test the updating feature as well as the functionality of the client.  Whilst this represents a good cross section of the 43000 computers that the Hosted Connector has been installed on, Scomis have found a number off issues which have occurred in the field on School Networks.

The table below describes some of the issues encountered and how to work around the issue or to permanently fix the issue.

Issue Reason Resolution
Remote Computer is not available The client will always attempt a direct (non-gateway) connection to the Remote Desktop.  This issue appears to be affecting London Grid for Learning Schools.

This happens because the Connection Detection has accessed port 3389 on the IP address for cl1 or cl2 clusters.  This could indicate that LGfL are allowing the school to see a 10.224.104.x address that is not from the Scomis network.

Block a the local school firewall
Install 6.10 and use the “Always Use Gateway” menu setting.  This can also be applied to users via GPO Preferences.
.net Exception Error There is a missing DLL from the C:\ProgramData\Scomis\HostedApps\EXE folder, or the school have an early version of the 6.10 connector which did not correctly initialise Delete the C:\ProgramData\Scomis\HostedApps folder and check the folder permissions.  Then restart the Hosted Apps Connector

Browse to the c:\ProgramData\Scomis\HostedApps folder and try to figure out which DLL is missing and then replace.

Re-install using the 6.10 MSI or later MSI

Windows 7 Client computers disconnect randomly from Remote Session V5.42 specified a specific gateway connection order overriding the one provided by  Version 6.08 and early versions of 6.10 removed this feature. Re-install using the 6.10 MSI or later MSI

Upgrade Client to Windows 10

.net Exception Error



The application is attempting to read the Windows Event logs to see if a particular Remote Desktop Disconnection event occurred.


The issue is caused by permissions to the event log.  Additional code has been inserted into the 6.10 client to suppress this issue.

Re-install using the 6.10 MSI or later MSI
Upgrade Issues (Permissions) Sometimes the C:\ProgramData\Scomis\HostedApps folder does not have the correct permissions which results in some users working and some that do not. The C:\ProgramData\Scomis\HostedApps folder should have the security group “Users” with “Full” control over the folder and sub folder.
Upgrade Issues (Missing files) Sometimes the C:\ProgramData\Scomis\HostedApps folder does not contain the correct files.  This may result in a “003 GUI” error. Delete the contents of the

C:\ProgramData\Scomis\HostedApps folder and verify the permissions as above.  Then run the connector again.

Remote Computer Not available (Avast AntiVirus is installed) Avast Antivirus is actively filtering remote desktop connections outbound.  It does this by preventing the Microsoft Remote Desktop application (MSTSC.exe) from establishing a connection. Modify the settings on Avast Antivirus Firewall.  Allow the following applications.







Cannot connect to the Remote Computer because of a security package error occurred in the transport layer This issue is more likely to affect Windows 10 computers when connecting to or  It is unknown why this issue occurs on some school computers.  It is possible that network Intrusion Detection or Internet Filtering may be breaking the “HTTP” negotiated connection to the Scomis 2016 Gateway servers.

This was first reported by internet users in 2017.  Advice from the internet is to clear down the credentials store, however this is not possible with the client as the credentials are removed automatically and recreated.

There is NO official advise from Microsoft on how to resolve this issue.

The issue can be worked around by using a different version of MSTSC, either by upgrading Windows 10 to the latest build or replacing the installed version with one from Windows 7 (not recommended).

Try setting the RDPClientTransport registry key in the HKCU.  This will force the Microsoft Remote Desktop application to use an older more reliable connection method.

Remote Computer is not available Despite connectivity to all of the gateway servers, it is possible that the local Windows computer is attempting to connect to the Gateway servers using UDP and failing.

More Information

Version 6.10 has a detection process built in that will insert the RDPClientTransport registry key if disconnection reason 50331661 is found in the TerminalServer-ClientActiveX event logs.

However if the application fails to inspect the event log, then the registry key will not be applied.

Client is detecting a non-gateway connection to port 3389 when it shouldn’t be possible It is possible that the .net managed code libraries are not correctly dealing with the detection of open ports.


A former SWGfL school experienced this issue.

Install 6.10 and use the “Always Use Gateway” menu setting.  This can also be applied to users via GPO Preferences.

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