The error in Azure Data Factory suggests an inconsistency in fetching or streaming data for preview. This can be due to transient network issues, hitting service limits, or issues with the source data. Ensure there are no connectivity issues on your end and that you're not exceeding any service quotas. Clearing your browser cache, trying different browsers, and refreshing metadata can sometimes solve these glitches. Additionally, enabling logging can provide more insight. If none of these solutions work, consider recreating the affected resources or reaching out to Azure Support for more specific assistance.