Proxy routed to Nekobox via AdGuard does not work in Firefox.

[Githubmaniak]

Please answer the following questions for yourself before submitting an issue

• [X] Filters were updated before reproducing an issue
• [X] I checked the knowledge base and found no answer
• [X] I checked to make sure that this issue has not already been filed

AdGuard version

4.3.1

Environment

• OS version: Android 10
• Device: SM-G955N

HTTPS filtering

• [X] yes, I do

Root access

• [ ] yes, I have it

Integration with AdGuard VPN

• [ ] yes, I do

Routing mode

Local VPN

Ad Blocking

AdGuard Base filter, AdGuard Mobile Ads filter

Privacy

No response

Social

AdGuard Social Media filter

Annoyances

AdGuard Annoyances filter, AdGuard Cookie Notices filter, AdGuard Popups filter, AdGuard Mobile App Banners filter, AdGuard Other Annoyances filter, AdGuard Widgets filter, Adblock Warning Removal List, I don't care about cookies

Security

Online Malicious URL Blocklist, NoCoin Filter List

Language-specific

List-KR, YousList

Other

Filter unblocking search ads and self-promotion, AdGuard DNS filter

Which DNS server do you use?

AdGuard DNS Non-filtering

DNS protocol

DNS-over-QUIC

Custom DNS

No response

What Stealth Mode options do you have enabled?

No response

Issue Details

Steps to reproduce:

1. Run Nekobox to start the service.
2. Enable proxy in AdGuard.
3. Run Firefox

Expected Behavior

Firefox must be connected to a proxy.

Actual Behavior

Firefox is not connected to a proxy and the original IP address is displayed on the web page that checks the IP address you are accessing, not the IP address such as CloudFlare.

Screenshots

Screenshot 1

Additional Information

Works correctly in browsers based on The Chromium Project.