We have several customers who are going to trial state after changing from being online to offline with their laptop. What do you think could be the cause of this please?

If an application was registered and it changed into trial state suddenly it must be due to any of the following possibilities:

1) If you are registering via a file key, your customer (or any cleaning tool) has deleted the license file from disk, so WinLicense does not find any license file to register your application.

2) If you are registering via a Registry key, your customer (or any cleaning tool) has deleted the registry key from the Windows Registry, so WinLicense does not find any Registry key to register your application.

3) If you are handling most of the customized dialog messages related with registration (in the Customized Dialog panel), you are probably not checking all possible license errors. Notice that if for example you are handling the MSG_ID_LICENSE_DAYS_EXPIRED (setting it as Disabled) and the license has expired by days, WinLicense will keep your application running even if the license has expired by days, because you are the responsible for checking if the license is expired (calling the WinLicense SDK functions). The same applies for any other Customized Dialog message that you set it as Disabled. You should call the function WLRegGetStatus to get information about each possible licensing error and know why the application went into Trial mode.