Troubleshooting Tip: FortiGate with 5G modem flapping when connecting to Verizon carrier using Static SIM Card
| Description | This article describes an under-investigation issue causing frequent disconnects when a FortiGate with a 5G modem connects to Verizon carrier using static SIM cards. |
| Scope | FortiGate platforms with integrated 5G modem, such as FortiGate-50G-5G and FortiGate Rugged-60G-5G. All FortiOS versions before FortiOS v7.4.12, v7.6.7, and v8.0.0. |
| Solution | This issue is tracked by internal Issue ID 1157402 and is reported for devices connecting to Verizon networks with static IP SIM cards (not dynamic IP addresses). When the issue occurs, the modem network interface disconnects every 5 minutes.
A FortiGate affected by the issue will show repeated disconnects and reconnects for the wwan interface in 'diagnose debug crashlog read' output reported by the nr5gd process.
2111: 2026-02-27 06:06:11 Interface wwan is brought down. process_id=1652, process_name="nr5gd" 2114: 2026-02-27 06:11:47 Interface wwan is brought down. process_id=1652, process_name="nr5gd"
Workaround: If a match for the issue is confirmed, a workaround can be applied directly to the internal modem during a maintenance window. Open a ticket with Fortinet Support.
Resolution: The issue is scheduled for fix in upcoming FortiOS releases v7.4.12, v7.6.7, and v8.0.0. Upgrade to a version with the fix when available.
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