While importing a CSV file into the Web TimeSheet the user encounters a Gateway Timeout error as seen in the picture given below.

The Gateway time out for SaaS instances at Replicon is set to 10 minutes. Hence, if a CSV file takes more than 10 minutes to upload its contents, the user encounters this error.
The data import or upload time is dependent upon the amount of data in the CSV file.

Make sure that the CSV file is divided into smaller chunks (files). The CSV files can be up to 80 kb in size, the maximum allowable would be 100 kb. If the CSV file size exceeds 100 kb the chances of a gateway timeout error increases.