UI3 error - "Unable to contact Blue Iris server"

[johndball]

Blue Iris version: 5.3.3.15 x64 (09 November 2020)
OS: Server 2016 Standard 1607 build 14393.4046
Stunnel 5.57 on Win64

Browser versions used:
Edge - 86.0.622.68
Firefox - 82.0.3
Chrome - 86.0.4240.198
Safari - (I dunno) Apple iPhone iOS 14.1

WAF/Firewalls:
Cloudflare page rule bypasses all caching, performance, and security
Untangle Firewall (edge firewall): No inspection of traffic to BlueIris coming from Cloudflare's network, drop everything else
OS firewall: Windows Firewall allows TCP 81, 443, 8443

Changes and auditing:
No changes to Cloudflare
No changes to Untangle
No changes to OS firewall (GPO controlled)
Blue Iris was upgraded to 5.4.4.15 then the errors started --> I'm not sure how to downgrade without losing settings...
Stunnel was upgraded to 5.57 and errors did not go away, rolled back to 5.51 and errors did not stop. Currently on 5.57

What does work: Blue Iris Web Sever settings - disabled "Use UI3 for non-IE browsers" will allow me to log in to BI.
Enabling "Use UI3 for non-IE browsers" results in a variety of errors. Sometimes "Unable to contact Blue Iris server", sometimes I can log in but get a "toastr" error, sometimes I can log in and see the cameras. If I continuously hit refresh (dozens of times), I can usually get logged in with no problem but will randomly error out, and sometimes Cloudflare throws up an error and says that Blue Iris is not responding.

In my mind, I would think rolling back BI would be the next logical step unless this is a known or recently identified problem in which I can wait for a patch. Ideas? Thanks in advance!

 

[johndball]

Few updates:
I rolled Blue Iris back to an August 2020 update with no fix.
I tried moving the "www" folder from BI4 to the BI5 folder and no fix.
I rolled back Stunnel and no fix.

Still poking and prodding trying to determine what is breaking down.

Edit: Rerouted some traffic internally. Was able to connect to

https://InternalServerName.johndball.com:8443/ui3.htm

and log in with no issue. Going back to htttps:/ExternalServerName.johndball.com:8443/ui3.htm brings up the "Unable to Contact Server" warning. I don't suspect it to be Blue Iris at this point, but the change logs (at least my client change logs) don't indicate any changes. Still prodding.

Edit 2: disabling use secure session keys and login page at least gets me authenticated to the server, but session status fails consistently.

 

[johndball]

Alright, reissued server side certs, reissued WAF certs, bypassed Cloudflare, direct IP to server from WAN, tried different ports, tried different application versions, tried getting fancy with the NAT'ing, disabled the firewall, modified the firewall, dropped in a different OU to disable all server-side Defender security (app locker, etc). Just short of rebuilding the 2016 server... The non-UI3 works fine, UI3 does not.

Do I have any idea of what is causing it? In the words of Chris Farley, "No idea!".

 

[SwampdogMash]

Alright, reissued server side certs, reissued WAF certs, bypassed Cloudflare, direct IP to server from WAN, tried different ports, tried different application versions, tried getting fancy with the NAT'ing, disabled the firewall, modified the firewall, dropped in a different OU to disable all server-side Defender security (app locker, etc). Just short of rebuilding the 2016 server... The non-UI3 works fine, UI3 does not.

Do I have any idea of what is causing it? In the words of Chris Farley, "No idea!".

I have a feeling I know... see my post here:

Error 502 with NGINX reverse proxy and BI > 5.3.1

Just registered to report the same issue. My setup: BlueIris 5.3.3.3 behind an Nginx reverse proxy at address: https://cctv.domain.com I use OAuth2 Proxy to control access on all other subdomains other than https://cctv.domain.com If start with a clean browser, I can visit...

ipcamtalk.com

 

[johndball]

@SwampdogMash , yup you nailed it. Let's hope it gets fixed. I've been down for some time now. For simplicity's sake, I'll move my replies to your thread.