Mostly inconsistent Internal Error 999 SSL proxying failures

[kielgillard]

Description

I am an iOS Developer. My work/employer uses DNS to resolve hostnames to test environments rather than production ones. However, we can only use these DNS servers when connected to the VPN.

Frequently, Proxyman's SSL Proxying is not reliable at intercepting and decrypting these requests and responses. I get frequent Internal Error 999 failures. But, I can intercept and decrypt requests and responses from non-work domains consistently, without any problems. Any suggestions why these requests might sometimes be successful?

Steps to Reproduce

1. Quit iOS Simulator.
2. Quit Proxyman,
3. Connect to VPN.
4. Change DNS server.
5. Launch Proxyman.
6. Build and run app in iOS Simulator.
7. See Proxyman inconsistently but mostly Internal Error 999 the requests.

Current Behavior

Internal Error 999 failures.

Expected Behavior

I can intercept and decrypt requests and responses, like I can when not using these DNS servers.

Environment

• App version: Proxyman Version 6.1.0 (60100) | macOS: Version 26.1 (Build 25B78)
• macOS version: Po-tah-toe.

[NghiaTranUIT]

@kielgillard it's because your VPN is not compatible with Proxyman.

Try not using VPN, and Proxyman works fine.

It's not a bug, it's show DNS + VPN works.

To workarond, you can use the Atlantis, which is working with all VPNs

[kielgillard]

it's because your VPN is not compatible with Proxyman.

@NghiaTranUIT Thanks for the response! I assume, somewhere, you've explained what this actually means. Where can I find that? Is there something about the VPN I could get reconfigured?

[NghiaTranUIT]

May I ask the name of your VPN app is? I can google to see if there is setting to fix it

[kielgillard]

May I ask the name of your VPN app is?

https://github.com/pritunl/pritunl

https://docs.pritunl.com/kb/vpn/

[kielgillard]

@NghiaTranUIT Any suggestions about configuring pritunl?

[NghiaTranUIT]

It seems Pritunl VPN uses their own certificate. I found this setting that allows this VPN to accept Proxyman Certificate (You can export it in Proxyman -> Certificate Menu -> Export Root Certificate -> DER or PEM)

[kielgillard]

Thanks, I'll look into it and let you know how I go.