If your computer is showing qb error h303 means that there is a requirement of additional configuration to the system on which the Quickbooks is installed. Well the causes of these error 303 is many such as IP address is not detected of the system on which Quickbooks file is located, file blockage issue, the .ND file is corrupted and configuration setting is incorrect. To resolve the issue you need to first download the quickbooks file doctor. This Quickbooks doctor file will automatically try to resolve the errors. But if you are still facing an error then contact Intuit quickbooks support on +18772433444 .