Short answer: check coverage, roaming, APN, and whether LTE/4G is more stable than 5G.
Try this
- Restart the phone.
- Move near a window or outdoor area.
- Select LTE/4G instead of 5G.
- Confirm the APN from your 4S service page.
- Check remaining data and validity.
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.