Hey Smita, getting OCR engine errors is a very common issue as they doesn't show in error logs. So to see OCR engine errors, you can use UiPath.Vision.Host Diagnostic Logs. The UiPath.Vision.Host Diagnostic Logs enables you to gather information regarding OCR engine errors.
You can enable the generation of diagnostic log files by adding following lines to <Installation Folder>\NLog.config file:
<target xsi:type="File" name="visionHostFile" fileName="${LogDirectory}/${shortdate}_VisionHost.log" layout="${time} ${level} ${message}" concurrentWrites="true" />
<logger name="UiPath.Vision.Host.exe" minLevel="Trace" writeTo="visionHostFile" final="true" />
Just keep in mind that, to edit the NLog.Config file you need administrator permissions.