Symptoms
Following eSIM migration, outgoing calls show the other line as default.
Use the following observations to establish that this is the specific failure described here, rather than an unrelated outage or different account:
- Failing behavior: Following eSIM migration, outgoing calls show the other line as default.
- Comparison to run: Compare Cellular line names, default voice line and contact-specific preferences.
- Pass condition: Calls to selected contacts use the intended active number.
Why It Happens
The same media or account may exist in several locations or profiles; distinguish local state, cloud account and operating-system permission.
Treat these as competing hypotheses, not confirmed diagnoses. Their implications are different:
- Default voice line reset — investigate this first only if the local state or controlled comparison supports it.
- Contacts remember a prior last-used line — a second layer that may survive a simple restart and requires a targeted check.
- eSIM display label does not match carrier number — investigate when the first two paths do not account for the observed behavior.
Before Making Changes
Avoid disabling the sole working emergency-capable line. A phone combines OS privacy controls, the app account, carrier or workplace restrictions, and local versus cloud content. A successful login does not establish that the specific data or permission is available. Write down the working configuration and, if available, export settings or create a test-only copy before changing account permissions, routes or file locations.
Make one change at a time, note the original value, and repeat the exact same test after each change. If the new outcome is worse, restore that single setting; a full reset would erase evidence and can create additional problems.
Problem-Specific Diagnosis
Begin with this controlled observation: Compare Cellular line names, default voice line and contact-specific preferences. Record the result and time; a vague report such as “sometimes fails” cannot distinguish the three hypotheses.
| Check | What to do | What the result tells you |
|---|---|---|
| Compare a working path | Compare Cellular line names, default voice line and contact-specific preferences. | If one controlled route works, the failed route is probably specific to a setting, permission, device, or service rather than a total outage. |
| Check the local state | Rename lines based on verified actual phone numbers. | This can expose or rule out default voice line reset without changing several settings together. |
| Inspect the deeper layer | Inspect per-contact preferred line and carrier activation state. | Use the evidence to separate contacts remember a prior last-used line from esim display label does not match carrier number; do not assume either is proven. |
If the local comparison is inconclusive, keep the current system unchanged while checking whether contacts remember a prior last-used line is consistent with the evidence. If not, investigate esim display label does not match carrier number rather than applying every possible fix.
Use Beginner for reversible checks; use Advanced only when the comparison indicates a deeper fault. Following eSIM migration, outgoing calls show the other line as default. Run a harmless test and write down the time, device/account, current status indicators and the exact difference from normal behavior. Compare Cellular line names, default voice line and contact-specific preferences. Do not erase logs or reset the device yet. Rename lines based on verified actual phone numbers. Confirm the relevant account, cable, selected output, permission or status before saving changes. If it is already correct, leave it alone and proceed; do not force a change just to try something. Set desired default voice line and test one trusted contact. Change only this one condition after recording the old value. If it does not improve the result, restore the former value rather than layering additional guesses on top. Calls to selected contacts use the intended active number. Repeat the same comparison used in step one. Record what improved, what remains unchanged and whether a reconnect or normal app restart changes the result. Stop here if the expected outcome is stable. Consider default voice line reset, contacts remember a prior last-used line and esim display label does not match carrier number separately. Compare evidence from the working and failing paths, and avoid interpreting a green status indicator as end-to-end proof. Compare Cellular line names, default voice line and contact-specific preferences. Inspect per-contact preferred line and carrier activation state. Focus on logs, state, permissions, protocol negotiation or version support relevant to this failure. Do not collect or share credentials, account tokens or unrelated private content. Ask carrier to verify transferred eSIM ICCID assignment when numbers appear mismatched. Use an isolated or test-only configuration where possible. Keep an explicit rollback path; do not weaken security, replace backup originals or bypass equipment protection to make one test pass. Calls to selected contacts use the intended active number. Observe the behavior through the original trigger again. If the change does not produce this measurable result, undo that change and escalate with the recorded facts, rather than repeating disruptive reset attempts.Step-by-Step Troubleshooting
Capture the failing state
Check the first reversible condition
Apply the lowest-risk targeted fix
Retest and document
Distinguish the competing root causes
Inspect the deeper system layer
Run a second independent isolation test
Validate stability and rollback readiness
Solution Checklist
Common Mistakes to Avoid
- Treating default voice line reset as certain before running the comparison: Compare Cellular line names, default voice line and contact-specific preferences.
- Trying several changes at once, such as modifying contacts remember a prior last-used line and esim display label does not match carrier number simultaneously, which makes the successful change impossible to identify.
- Ignoring the safety boundary: Avoid disabling the sole working emergency-capable line.
- Assuming that a status label or progress indicator guarantees the actual action completed; verify the outcome independently.
How to Verify the Fix
Calls to selected contacts use the intended active number.
- Repeat the original failing action under equivalent conditions: Following eSIM migration, outgoing calls show the other line as default.
- Run the control again: Compare Cellular line names, default voice line and contact-specific preferences.
- Check the positive pass condition: Calls to selected contacts use the intended active number.
- Recheck after a normal restart, reconnection or scheduled cycle only when it is safe and relevant.
A single passing attempt is useful but may conceal intermittent failures. Record whether the fix survives the triggering condition without requiring a daily workaround.
If the Problem Continues
Use the deeper comparison rather than repeating the first steps: Inspect per-contact preferred line and carrier activation state. Ask carrier to verify transferred eSIM ICCID assignment when numbers appear mismatched.
Support should receive device model, app version, exact permission wording and a nonprivate reproduction path; do not send photos, one-time passcodes or contact databases.
If the issue affects money, alarms, shared business records, or protective power equipment, stop risky experiments and use the official administrator, provider or manufacturer channel.
Prevent Recurrence
- Keep a record of the previously failing condition: Compare Cellular line names, default voice line and contact-specific preferences.
- Preserve the corrected behavior: Calls to selected contacts use the intended active number.
- Review backup status and app permissions after account, SIM and device changes; retain local originals until a restore has been confirmed.
- Review configuration or hardware changes that could reintroduce default voice line reset.
Frequently Asked Questions
Does this symptom prove default voice line reset?
No. Start with the controlled comparison: Compare Cellular line names, default voice line and contact-specific preferences. Only treat default voice line reset as a candidate until the evidence supports it.
What if the first two checks do not change anything?
Move to a different layer rather than repeating the same action: Inspect per-contact preferred line and carrier activation state. That helps determine whether contacts remember a prior last-used line or esim display label does not match carrier number fits the symptoms.
How do I know the repair actually worked?
Use this outcome, not just an on-screen status message: Calls to selected contacts use the intended active number. Keep a record of the working state for future troubleshooting.