This is the code for my dynamic page that sometimes reports an error but sometimes works.

dynamicpagewitherror.ps1

$DynamicBacklogListPage = New-UDPage -url "/backlog/:server/:folder" -EndPoint {
    Param($server, $folder)
    New-UDRow -endpoint {
        $query = "Select [BacklogFiles] from [dbo].[dfsrlatestdata] Where Server = `'$server`' and ReplicatedFolder = `'$folder`'"
        $BacklogFileList = @(
            Foreach ($item in $(invoke-sqlcmd -MaxCharLength 25600 -connectionString $sqlconnectionstring -query $query | convertto-json | convertfrom-json).BacklogFiles.Split(',')) {
                new-object psobject -Property @{
                    Filename = $item
                }
            }
        )
        $GridProperties = @{
            Title      = "First 100 backlogged files for $folder share on $server"
            headers    = @('File')
            properties = @('Filename')
            PageSize   = 100
            Endpoint   = {
                $BacklogFileList | out-udgriddata
            }
        }
        New-UDGrid @GridProperties
    }
    New-UDRow -Endpoint {
        $sqldata = invoke-sqlcmd -ConnectionString $SQLConnectionString -query "Select
            DATEADD(HOUR, DATEDIFF(HOUR, 0, [TimeStamp]), 0) AS TimeStamp,
            Backlog
            from [dfsralldata]
            WHERE Server = `'$server`' AND
            replicatedFolder = `'$folder`'" | sort-object -Property TimeStamp | select-object backlog, @{l='timestamp';e={$_.timestamp.ToString()}}
        New-UDChart -Title "Backlog History" -Type Line -Endpoint {
            $sqldata | Out-UDChartData -LabelProperty "TimeStamp" -DataProperty "backlog"
        }
    }
}