START WITH THE SYMPTOM
What does slow look like?
Open a matching symptom for one focused check. This page does not run a speed test or upload logs.
Latency is shown, but every page times out
Check the client's connections list: does the browser request appear, and does it use the intended node? If absent, follow the device guide to check System Proxy; if it uses DIRECT, inspect the rule. A node's latency test does not prove the browser is connected.
Check proxy setup for your deviceOnly HY2 times out; Trojan works
HY2 uses UDP. Compare real page requests and record whether both entries use the same exit. Configuration and server problems can also cause timeouts; TCP connectivity alone does not rule them out. Retain certificate verification and the supplied settings.
Compare protocol behaviorWi-Fi is slow, but a hotspot works
Keep the device, node, protocol and page fixed; try each network three times and record the time. This narrows the investigation but does not distinguish Wi-Fi interference, gateway policy or the upstream path.
Record a comparable testOnly one site fails, or only AI is slow
Try two other HTTPS sites. If only one destination fails, check its status and exact error. Handle HTTP responses such as 403 or 429 separately from connection timeouts. AI response time also includes queuing and model processing.
Check the destination and AI connectionIt connects, then disconnects later
Record when it drops and whether the device slept, locked or changed networks, then keep a redacted log from that time. Compare another protocol with other conditions fixed. If it happens on only one network, include that comparison.
Prepare a disconnect reportThree checks before a full speed test
Keep the current configuration and check subscription validity and remaining data. Do not begin by reinstalling the client; record each setting so you can restore it.
Confirm the browser uses the selected node
Open an HTTPS page and inspect its matched rule and node in the client's connections list. Check the browser's current exit too. A subscription card or latency figure does not replace this check.
Compare available protocols on the same page
Keep the device, Wi-Fi and page fixed while comparing available HY2 and Trojan entries. Try each three times and record successes and failures. If their exits differ, record that too; the protocol is then not the only changed variable.
Keep the node fixed and compare another network
On the same device, compare a mobile hotspot and then restore the original network. Failure on only one network warrants checking that path; it does not by itself prove throttling or blocking. If both fail, send the comparison to support.
Read throughput, latency, jitter and loss separately
A result describes the connection from your device to the test destination under those conditions. A different destination, Wi-Fi, node or time can change it. Test platforms also differ, so one platform's score does not describe every app.
Record the metrics below alongside the conditions and raw results, then compare like-for-like runs. Do not infer long-term bandwidth from the best single result.
| Metric | What it describes | What it does not prove |
|---|---|---|
| Download / upload throughput | Transfer rate on the tested path | Guaranteed bandwidth for every destination or time |
| Idle / loaded latency | Round-trip delay without or during transfers | Model generation speed |
| Jitter | Variation between latency measurements | Average throughput |
| Packet loss / request failures | Loss or failures in that test method | The failure cause of every protocol |
Change one condition at a time
Confirm the subscription is valid and a node is selected, then record System Proxy, mobile VPN or TUN mode. Keep your configuration and compare one node or protocol at a time, rather than changing the client, DNS and Wi-Fi together.
Use the same destination and pause large downloads or updates. As a practical method, repeat each group at least three times, compare its median and failures, then run another group at your usual time. This does not establish a long-term reliability guarantee.
Cloudflare Speed Test is one available tool, measuring its own test network rather than proving the route to an AI platform. Speed tests transfer data; uploads and downloads count toward NailongVPN's allowance.
- Record the device, client version, local network, node and protocol.
- Record local date, time, time zone and test destination.
- Keep every result and failure count before summarizing the median, rather than selecting the fastest run.
A TCP test cannot validate a failing HY2 UDP connection
HY2 (Hysteria2) uses UDP. A successful TCP port connection does not validate its UDP path, authentication, certificate or obfuscation. Use real client logs and browsing tests; a timeout can have several causes, as covered in official troubleshooting.
Try the subscription's Trojan option on the same network as a comparison. If Trojan works while HY2 times out, record each node, time and log before contacting support. Retain the subscription's certificate and obfuscation configuration.
AI first-response time depends on more than the network
Waiting for an AI response includes connection setup, provider queuing, model processing and returned content. Test ordinary HTTPS first, then inspect the AI request's status and timing. Lower latency does not guarantee faster inference or better answers.
If the browser works while a terminal or SDK times out, first check its proxy. For responses such as 401, 403 or 429, follow the provider's authentication, permission or rate-limit guidance rather than treating every error as a VPN speed issue.
Give support reproducible results
Provide the failing step, device and client version, network type, node and protocol, test time, destination and error text. A working and failing node compared under the same conditions makes the next check easier to identify.
Redact full subscription URLs, API keys, passwords, verification codes and session credentials from screenshots and logs. These are methods for your own tests, not measured NailongVPN performance results.