For cost purposes we use 2 different SIP providers (Flowroute and Plivo) to handle calls to our direct lines. 80% of our incoming calls are routed through Plivo and 20% are routed through Flowroute. A couple weeks ago we noticed that a significant number of incoming calls on our Plivo DIDs stated to pass through bad/extra caller ID info (ex. verstat=TN-Validation-Passed is added to the name or phone number, making it impossible to call back using redial, etc.), but not all of them. We were able to narrow it down to callers with T-Mobile (not Sprint surprisingly, also not Google Fi, which also uses T-Mobile towers).
We opened up a ticket with Plivo with EXTENSIVE logs of unaffected calls and affected calls, hoping it would be an easy fix on their end. After 9 days this problem still wasn't fixed. When I randomly looked at our incoming call log it was clear to see that we no longer had any calls with "verstat=TN-Validation-Passed" appended to them. I assumed the problem was fixed and attempted to make a test call to my DID using a T-Mobile phone to verify.
This is where the huge problem starts. The call did nothing. It stayed on the "Calling" status on the cell phone screen. No time counter or anything. After accidentally setting the phone down in this state the call went through after TWO FULL MINUTES. This has been verified on numerous different cell phones with the same behavior. Verizon phones don't have this issue. Sprint phones don't have this issue. My crappy Google Fi phone doesn't have this issue.
-recap-
I can call my desk phone (Plivo) from my cell phone and the call goes through perfectly.
I then call the same phone from my coworker's T-Mobile cell phone and it sits on the "Calling" screen on his iPhone for 2 minutes, connects the call, starts counting call time, and then my phone rings.
My coworker's same T-Mobile phone calls one of our DIDs handled by Flowroute and the calls goes through just fine.
After discovering the fact that we were clearly unknowingly missing out on a number of incoming phone calls we created a new critical ticket with Plivo. They have been spinning their wheels for over a day and are now starting to throw in language indicating that it's our 3CX server's fault for not responding. They indicate that it's likely related to Stir/Shaken but are still looking into it while we continue to miss calls blindly.
I did see on the 3CX forum that this "verstat=TN-Validation-Passed" issue has to do with Stir/Shaken, but don't know enough about that to even begin to think I could troubleshoot anything on our end.
Anyone have any ideas on this? Simply waiting for Plivo to figure it out seems like the only thing to do given the call behavior, but doing nothing is not a good look to our bosses.
We opened up a ticket with Plivo with EXTENSIVE logs of unaffected calls and affected calls, hoping it would be an easy fix on their end. After 9 days this problem still wasn't fixed. When I randomly looked at our incoming call log it was clear to see that we no longer had any calls with "verstat=TN-Validation-Passed" appended to them. I assumed the problem was fixed and attempted to make a test call to my DID using a T-Mobile phone to verify.
This is where the huge problem starts. The call did nothing. It stayed on the "Calling" status on the cell phone screen. No time counter or anything. After accidentally setting the phone down in this state the call went through after TWO FULL MINUTES. This has been verified on numerous different cell phones with the same behavior. Verizon phones don't have this issue. Sprint phones don't have this issue. My crappy Google Fi phone doesn't have this issue.
-recap-
I can call my desk phone (Plivo) from my cell phone and the call goes through perfectly.
I then call the same phone from my coworker's T-Mobile cell phone and it sits on the "Calling" screen on his iPhone for 2 minutes, connects the call, starts counting call time, and then my phone rings.
My coworker's same T-Mobile phone calls one of our DIDs handled by Flowroute and the calls goes through just fine.
After discovering the fact that we were clearly unknowingly missing out on a number of incoming phone calls we created a new critical ticket with Plivo. They have been spinning their wheels for over a day and are now starting to throw in language indicating that it's our 3CX server's fault for not responding. They indicate that it's likely related to Stir/Shaken but are still looking into it while we continue to miss calls blindly.
I did see on the 3CX forum that this "verstat=TN-Validation-Passed" issue has to do with Stir/Shaken, but don't know enough about that to even begin to think I could troubleshoot anything on our end.
Anyone have any ideas on this? Simply waiting for Plivo to figure it out seems like the only thing to do given the call behavior, but doing nothing is not a good look to our bosses.
