Registering a client returns SIM Wrapper Error 21 (0)

1. Check your Serial Number and Access Code for accuracy, try to copy and paste
2. Confirm you have enough licenses to cover all the active sessions
   
3. If neither of the above options work, this is likely the result of a license file that has a different set of codes
   
1. If there is a working client, copy the codes from that computer and try it on this one
   
1. If this works, the Serial Number and Access Code you are trying to use do not match the ones contained in the license file. Either update the license file along with all the clients, or simply use the working codes taken from the working computer until you are ready to update all the clients with the new codes. 
2. Look for an old license report and try codes from that
   
3. Update the license file with the latest copy located in the customer folder, then update all the clients
   

Registering a client returns a SIM Wrapper Error 14 (0)

1. You do not have permission to write to the registry, review this article (link).
   

Registering a client returns a SIM Wrapper Error 20 (0)

1. Double-check the Server and Port, this is the FLM server computer and TCP port
1. Make sure you can ping the FLM server computer
2. If using a hostname, try using an IP address instead
   
2. Make sure the Predator FLM Server is running
   
3. Make sure the firewall is either off or allowing the TCP port (typically 50000) through
   
4. Make sure .NET 3.5 is installed (How to Enable .NET 3.5 Framework on Windows 10)
   

Unable to start the Predator FLM Service

1. Open the Predator FLM Service Manager, click Service Serial/Access Startup Check
   
1. If it says this product appears to be licensed correctly, then the license is not the problem
   
2. If it says its not licensed correctly, close all windows, open the Predator FLM Service Manager, click Upgrade Service Serial/Access, either make sure the SIM is attached or you have valid temporary codes
   
2. Check to make sure you have the "PFLM Service.license" file in the same folder as PFLM Service.exe
   
1. The name is important, it must be "PFLM Service.license"
   
3. Check to make sure the Port is not in use by another program
   
1. How to Use NETSTAT to Locate TCP Socket Connections
   
4. Check to make sure the Port is not blocked by a firewall
   
5. Check to make sure the PFLM service is not blocked by an Anti-Virus program

The Predator FLM Service is stuck on "Starting"

1. Assuming the Predator FLM Server was already working, this is likely caused by the service being started to soon after being stopped
   
2. Open task manager, go to Details tab, look for PFLM Service.exe, end that task
   
3. After it disappears from the Details tab, try starting it again

After pressing Start Service, the error "The service appears unable to start, do you want to continue to wait" appears

1. See the two topics above for a possible solution

The buttons are grayed out in the Predator FLM Service Manager

1. Close it, then reopen it