How do I solve Error 503?

[Khartalia]

Hi all...I use ZOOM phone service through my work account, but I work from home. Each morning I start up ZOOM, I need to completely log out of ZOOM and restart the app before I can make calls. Several days ago, the resetting process no longer worked. ZOOM will not connect for phone calls (Service Unavailable: Code 503). The phone pad stays greyed out, so I can't make any calls. When I try to look at the details of the error, it says Registration Error. I have tried rebooting the app multiple times, and rebooting my computer and modem/router several times. Nothing is working. ZOOM continues to attempt connection all day, but no success. It was suggested that I turn off my SIP ALG setting in my modem, but nobody seems to know how to navigate around within my router settings to find this one setting, including my service provider who gave us the modem!

All recommendations welcome...

[Eliot]

with a little information, we may be able to figure this out.

1.  what is make and model number of your modem and router at your home? 

2. which internet service provider are you using at your home?

3.  what zoom client and client version number are you using?

4.  what is the make and model number and operating system of your laptop?

thanks,  eliot

[Khartalia]

1. Gateway CGM4140COM (modem and router are one unit)

2. Rogers

3. I don't know about the client, but the version is 5.14.2. I use it through my workplace ZOOM account (Trillium College). 

4. Windows 11

[Eliot]

hi khartalia,

i checked the rogers community and found a post about the necessity of disable sip/alg.  i suggest that you contact rogers to have sip/alg turned off.

SIP / ALG setting for VOIP Phones - Rogers Community

thanks,  eliot

[Khartalia]

Thank you for that suggestion, Elliot. Unfortunately, Rogers is totally unable/unwilling to help with this. They keep telling me it is already off, but most external sources say otherwise. They have also hidden the section in the router's direct access controls to shut this off. Without their help to navigate the router's menus, it has proven impossible to find this setting. 

[Eliot]

you might consider posting the question to the rogers community.

you could ask rogers to replace your modem/router with a more up to date device.

zoom phone also has a network tool that checks to see if the phone phone can connect to zoom's sip server for registration.  it's free.  your company admin just submits a ticket to support to enable it.  after the network tool is enabled, you go to your zoom portal, zoom phone and you will see the network tool.  you click it to run and you will see if it encounters any network issues getting from your home network to zoom sip server.

Network Diagnostics

Network Diagnostics

Run a test to evaluate the quality of your network, it will request access to your microphone to simulate a call.Test

Tested Time: Wednesday, Apr 5, 2023, 04:46:10 (GMT-7:00)

Your Public IP

71.191.167.73:61078

 Ready Connectivity to Zoom Web

 

 Ready Connectivity to signaling server

 

 

Server Address

162.12.232.84:30162

Latency (RTT)

Latency (RTT) tooltip

Avg (ms)

20

Max (ms)

22

Packet Loss

Packet Loss tooltip

Avg (%)

Sending:0

Receiving:0

Max (%)

Sending:0

Receiving:0

Jitter

Jitter tooltip

Avg (ms)

Sending:0

Receiving:0

Max (ms)

Sending:1

Receiving:1

Codec

Sending:opus

Receiving:opus

Clock Rate (KHz)

Sending:48

Receiving:48

https://support.zoom.us/hc/en-us/articles/7814027751821-Simulating-VoIP-calls-using-the-network-tool

finally, you could put in your own wifi router and just use rogers for the modem.  i do not know how rogers works.  in usa, the customer end of a fiber circuit is an optical network terminal ("ont").  the router may be able to be connected directly to the ont.

thanks,  eliot