Short answer: slow speed is usually related to coverage, network congestion, signal mode, or remaining high-speed data.
Try this on iPhone
- Move to a different location and test again.
- Restart the iPhone.
- Confirm the 4S eSIM label is selected for mobile data.
- Try LTE/4G if 5G is unstable.
- Check whether your plan has remaining data or fair-use limits.
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.
When contacting support, include your order email, ICCID if available, destination, phone model, and screenshots of the error or SIM/eSIM settings page.