Sometimes, you may be able to view the preview thumbnail for a particular plate read (first image), but once you click to view the full result, you receive a "Remote agent not connected" error (second image). This can happen from both the Dashboard or Advanced Search tabs

To troubleshoot, please check the following common cases
1. AlprLink not running
AlprLink is a service that communicates between each agent and the webserver. It must be running in order for local images to be retrieved from the agent. From the webserver, check the agent configuration page (Configuration > Agents) for a green thumbs up

You can also check the AlprLink status from the local agent's GUI. Click the Services tab in the upper left, and confirm that there is a green circle next to the link service
2. Rolling database out of disk space
If AlprLink is running and you still get a remote agent not connected error, it may be due to limited disk space. The thumbnail images are stored directly on the webserver along with text metadata (plate, state, time, etc) according to our 60 day retention policy. Conversely, the full images that display in the popup are stored in a rolling database on the agent's computer. You determine the amount of disk space that is allocated for the local rolling database, so its retention policy will not necessary line up with the 60 day policy for thumbnails and metadata. 
If you check your agent's configuration in the webserver, there are fields for Oldest Image and Disk Usage at the top of the page. Further down the page under Agent Parameters, you can modify the image disk quota. Once images from your reads exceed your quota, the oldest ones will be deleted to make more space. Each image uses 100-300 KB depending on resolution and image quality (configurable), so you can estimate how many days retention you will get based on the expected number of reads per day.

Video storage (if enabled) also occurs in a rolling database. However, the space required is much more variable since the frame rate, resolution, compression quality, and length of capture all impact the size of the resulting video clip. You can estimate between 500 KB to 20 MB per 10 second video.