This article will help you in verifying and resolving the date format error. You may most likely encounter this issue due to invalid or distinct date format settings on your integrator.IO compared to your NetSuite account.
Hence, you need to verify the date format which you have set in NetSuite at both User level and Account level.
At User level: Go to Set Preferences > Date Format
At Account level: Go to Setup > Company > General Preferences > Date Format