STEP 1: Check Your Hardware & Compatibility
Device Unlock: Ensure your handset is not locked to another network. If it is, you must contact your previous provider to request an unlock before the ONSIM SIM will function.
Physical SIMs: Verify the SIM is inserted correctly. Our SIMs use a 3-in-1 "pop-out" design; ensure you are using the correct size for your tray.
eSIMs: Confirm the eSIM profile is active on your device. View the eSIM Installation Guide here.
Supported Devices: Our service requires specific carrier files. Check if your device is supported here.
STEP 2: Refresh the Network Connection
Force your device to re-register with the network:
Enable Flight Mode.
Wait for one full minute.
Disable Flight Mode.
If this doesn't work, perform a full restart of your handset.
STEP 3: Verify Device Settings
Do Not Disturb: Ensure this mode is switched OFF.
Blacklists: Check that you haven't accidentally blocked the number trying to reach you.
VoLTE: This setting must be enabled for full service functionality. Check VoLTE settings here.
Still having issues?
If you have completed the steps above and still require assistance, please email support@onsim.uk or login to your online portal and raise a support ticket.
Important: To investigate effectively, our technicians require specific data. Simply stating "it’s not working" will delay the resolution. Please copy, paste, and complete the template below in your email.
Support Ticket Template
Issue Description: (Include any error messages heard or seen) Impact: (Inbound calls / Outbound calls / Both) Restart Performed?: (Yes / No) SIMs Affected: (Provide the mobile numbers of all affected SIMs) Current Postcode: (Where the issue is occurring)
Call Example (Inbound)
Time & Date:
Number Dialled:
Caller's Number:
Error Tone/Message:
Call Example (Outbound)
Time & Date:
Number Dialled:
Number you called from:
Error Tone/Message: