Short answer: PDP Authentication Failure means the phone or network could not complete mobile-data authentication for the eSIM.
First checks
- Confirm the 4S eSIM is selected as mobile data.
- Turn on data roaming for that same eSIM line.
- Restart the phone.
- Try LTE/4G instead of 5G.
- For Android/Samsung/Google Pixel, confirm the APN shown on your 4S service page.
Why timing matters
Install your eSIM within 1 month before departure. Some carriers run authentication and compliance checks for eSIM profiles, and installing too early may increase the chance of PDP Authentication Failure or a similar network authentication issue.
For APN settings, the important field is APN. The Name field is only a local display name and can be anything recognizable, such as 4S, Travel, or your destination.
Need help?
Contact 4S support through support@4s.net, a Zendesk support ticket, or Zendesk live chat. Do not reply to hi@4s.net; it is an automatic order and installation email sender.
If the error continues, contact support with the exact error text, destination, phone model, ICCID, APN screen, and mobile data line selection screenshot.