Issue
When you open a trend you get the following message
Environment
Vista 5.x.x
Cause
The period selected in the trend chart does not exist in the trends associated with that chart.
In the sample below the trend only store 1 days worth of information and the chart is requesting last weeks information.
This would result in this type of error.
Resolution
Modify the period selected in the chart so that trend values that are logged will be displayed.