First of all, check the order of the sources in the scene. The alert widget may simply be hidden by another source. The higher the source is in the list, the higher its priority.

Another possible cause may be an outdated version of the CLR Browser Source Plugin. You need to download it using the following links:

• For the 32-bit version of OBS Classic: http://catchexception.org/CBSP/CLRBrowserSourcePlugin-20140909x86.zip
• For the 64-bit version of OBS Classic: http://catchexception.org/CBSP/CLRBrowserSourcePlugin-20140909x64.zip

You should also note that the widget won't display anything until an alert appears.

The fundraising widget is not displayed

The most likely cause is that you simply didn't create a goal. After entering the goal data, click "Create goal".
You should also check the order of the sources in the scene. The fundraising widget may simply be hidden by another source. The higher the source is in the list, the higher its priority.