I just tested three FPL numbers. Incoming calls are working.
1. What brand and model modem are you using? Ensure that it's in bridge mode if it's a modem/router combo or gateway. Contact your ISP if you need help enabling bridge mode.
2. In Merlin, navigate to Advanced Settings-->WAN-->NAT Passthrough
Disable SIP Passthrough.
3. In Merlin, navigate to General–>Tools-->Other settings
a) change UDP Timeout: Assured to 115 seconds
b) change UDP Timeout: Unreplied to 15 seconds
3. Dial *79 to disable Do Not Disturb.
4. In your ATA, what are you using for Primary SIP Server?
a) Ensure that "Use Random SIP Port" is enabled.
b) SIP REGISTER Contact Header Uses should be set to WAN address
c) Register Expiration is 60 minutes (note that this setting is in minutes and not seconds)
d) SIP Registration Failure Retry Wait Time should be 120 seconds
e) SIP OPTIONS/NOTIFY Keep Alive Interval should be 20 seconds.
Note that 3a, 3b, 4d, and 4e satisfy the following:
UDP Unreplied Timeout (in your router) < NAT Keep-alive Interval (in your ATA; for Obihai ATAs this is X_KeepAliveExpires; for Grandstream, the setting is SIP OPTIONS Keep Alive Interval) < UDP Assured Timeout (in your router) < SIP Registration Failure Retry Wait Time (or RegisterRetryInterval in Obihai ATAs)
“<“ means less than.
Refer to point D from
viewtopic.php?f=8&t=20199#p78976.
5. Login at
https://www.freephoneline.ca/showSipSettings.
What does "SIP status" show?
Please note that if "SIP User Agent" does not reflect a device you're using, someone else is using your Freephoneline VoIP unlock key.
Only one registration per ATA FXS Port is permitted at any time per Freephoneline VoIP unlock key. Registration is a requirement for incoming calls but not for outgoing calls.
6. If you find after rebooting the ATA you still have problems, change Primary SIP Server to "voip4.freephoneline.ca:6060" without the quotation marks.