Issue

The Home Location Register (HLR) LookUp Service returns the numbers marked with the "Unknown" status, making determining the leads' validity difficult.

Possible Causes

An "unknown" Home Location Register (HLR) status can result from several reasons:

Reason 1. Invalid or Inactive Number

The number may not be allocated, no longer in use, or never have existed.

Reason 2. Number Portability Issues

The number might have been ported to another network, but the lookup service can't resolve the current operator.

Reason 3. Operator Doesn't Respond to HLR Queries

Some mobile carriers restrict or block HLR lookups to prevent misuse.

Reason 4. HLR Provider Error or Timeout

The HLR query might have timed out or encountered a backend issue.

Reason 5. International Routing Problems

If you're performing a lookup for a number from another country, routing or interconnect issues can lead to "unknown."

Reason 6. Temporary Network Issue

The mobile network might be temporarily unreachable or have issues.

Reason 7. Wrong Format

The number might be submitted in an incorrect format (missing country code, extra characters, etc.)

Troubleshooting Steps

To verify if the lead is valid:

1. Verify number format (include full international format, e.g., +1XXXXXXXXXX).
2. Test with another known-good number from the same carrier/network.
3. Check if other lookups are also failing (might be a provider issue).
4. Wait and retry – sometimes it's a temporary network or system issue.
5. Contact our support team for specific insight/logs on the failed query.

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NOTE

Please see the Results section for more HLR statuses.