Yealink T53 not provisioning on Hosted 3CX

[PracticalITSolutions]

I am new to this forum - but I have been using 3CX for a couple of years with clients on my phone and on my Windows Desktop.
Recently I decided to buy a Yealink T53 and followed instructions and it successfully provisioned! It was configured as MY phone - I am the ADMIN/SYSTEM OWNER - not sure that matters.
Then I attempted to add an ADDITIONAL T53 for another (non System Owner) User. Could not make it work.
I have been struggling with this for about a week and have tried lots of different things. I am now at a point where I can't even provision a T53 for myself - even though I was originally successful at doing so (yes I removed it so I have erased what little success I previously had).

Through examining several logs and attempting several times, I think I have found part of the problem, but maybe it is not related at all. Hopefully someone can shed light on this for me.
From the 3cxManagementConsole.log file, I see the following which feels like it is the issue:
2023/08/01 12:11:48.986|19169|0038|Inf|PRV: Requested file '/provisioning/1vzgskg0n7sd/805ec0829b3a.boot' is not found in file system 2023/08/01 12:11:48.986|19169|0038|Inf|PRV: error getting /provisioning/1vzgskg0n7sd/805ec0829b3a.boot requested from 75.174.253.129 2023/08/01 12:11:49.231|19169|0038|Inf|PRV: Requested file '/provisioning/1vzgskg0n7sd/y000000000000.boot' is not found in file system 2023/08/01 12:11:49.231|19169|0038|Inf|PRV: error getting /provisioning/1vzgskg0n7sd/y000000000000.boot requested from 75.174.253.129 2023/08/01 12:11:49.568|19169|0038|Inf|PRV: Timezone 'GMT-7:00 United States-Mountain Time' is assigned by group to the phone Yealink T53 of extension 10 2023/08/01 12:11:50.013|19169|0070|Inf|PRV: Timezone 'GMT-7:00 United States-Mountain Time' is assigned by group to the phone Yealink T53 of extension 10 2023/08/01 12:11:52.040|19169|0070|Inf|PRV: Requested file '/provisioning/1vzgskg0n7sd/firmware/yealink//T53.rom' is not found in file system 2023/08/01 12:11:52.040|19169|0070|Inf|PRV: error getting /provisioning/1vzgskg0n7sd/firmware/yealink//T53.rom requested from 75.174.253.129 2023/08/01 12:11:55.373|19169|0038|Inf|PRV: Requested file '/provisioning/1vzgskg0n7sd/firmware/yealink//YL0000000000.rom' is not found in file system 2023/08/01 12:11:55.373|19169|0038|Inf|PRV: error getting /provisioning/1vzgskg0n7sd/firmware/yealink//YL0000000000.rom requested from 75.174.253.129
The 805ec0829b3a is indeed the MAC of the phone I keep factory resetting and plugging in.

 

[TheodorosG_3CX]

What is the current firmware version of the phone?
Also what is the provisioning method?

 

[PracticalITSolutions]

Firmware is 96.86.0.74
Provisioned through the Admin console and selected "Router Phone". Entered MAC address, etc - am I answering the question you are asking?

 

[TheodorosG_3CX]

I can see the RPS request was created today. Have you checked whether the public ip of the remote location is blacklisted in the PBX?

 

[PracticalITSolutions]

By REMOTE LOCATION you mean my office - where I am typing these messages and have the phones? Full disclosure, I have struggled with that a LOT last week - but am not having that trouble today.
Just checked - oddly, there IS a new entry in the IP Blacklist table - but it is not for my Public IP. That IP does NOT ring a bell with me.

 

[TheodorosG_3CX]

Please edit your screenshot and do not provide this information in public.

Since the PBX is 3CX Hosted the remote location is from where the ip phone is located. At this point the device is not provisioned?

 

[PracticalITSolutions]

Correct, the device still shows "No Service" instead of the expected extension # and name.

 

[TheodorosG_3CX]

Have you tried to delete the device from the extension, factory reset and provision from scratch?

 

[PracticalITSolutions]

Yes. Many times.

 

[PracticalITSolutions]

Brainstorming - I have a Polycom phone that is on this same network (same Public IP) - it services a Google Voice account/number. Could it be causing issues? I just now unplugged it.

 

[TheodorosG_3CX]

Have you added more phones to a specific extension?

 

[PracticalITSolutions]

I currently only have ONE IP Phone configured for ONE (mine) extension.

Update. I came home early. Wanting to test a theory, I brought the T53 phone home with me. I plugged it in to my home network and IT IS WORKING! It provisioned and is displaying my extension number and name!
So, it must be something with my office network?
When I return to the office tomorrow, I will bring the phone with me to see if it works there.

 

[TheodorosG_3CX]

Most probably something is blocking on this network.

 

[PracticalITSolutions]

I really want to resolve that - how can I investigate what the block is?

 

[PracticalITSolutions]

UPDATE
Sometime last week when I was struggling with provisioning, I had DISABLED "SIP ALG". Not even sure what it does, but I saw a thread that suggested that could be a problem. This morning I RE-ENABLED the SIP ALG. In addition, the POLYCOM phone that is connecting to Google Voice is still unplugged. Somehow that made a difference - or something completely unrelated that I can't put my finger on.

I have now successfully provisioned 2 Yealink T53 devices in my OFFICE location in addition to the T53 device that is provisioned at my HOME location.

SUCCESS!