Why Your Mobile Proxy Keeps Disconnecting (and How to Fix It)

your mobile proxy keeps dropping in the middle of a job. the script runs fine for a few minutes, then the connection dies, the IP changes, or everything just hangs. this is the single most common message I get, and almost every time it comes down to one of about eight causes.

I run the hardware farm behind Singapore Mobile Proxy. real phones, real SIMs from SingTel, M1, and StarHub, on the live carrier network. so when a connection drops, I can usually tell from the symptom alone whether it is the carrier, the provider, your client code, or the site you are hitting. here are the eight causes in the order I check them, each with its fix.

first, answer one question

before anything else: is the IP changing, or is the connection actually dropping? these feel the same from the outside but they are completely different problems.

log the proxy IP on every request. if the IP changes but your requests keep succeeding, that is rotation, and it is usually normal. if the connection times out, refuses, or hangs, that is a real disconnect. most people never make this distinction, so they try to fix a disconnect when what they actually have is rotation they should have designed around. figure out which one you have first, because it splits the whole problem in half.

cause 1: carrier IP rotation (this one is normal)

every mobile carrier puts its devices behind carrier-grade NAT, and the public IP assigned to a SIM changes periodically as a normal part of how the network manages addresses. this is not your proxy breaking. it is the carrier doing exactly what it does for every real phone in Singapore. if you want the full picture of why mobile IPs behave this way, what is a mobile proxy covers the carrier-grade NAT mechanics.

the fix is not to stop the rotation, it is to connect through a stable gateway endpoint that stays constant while the IP behind it changes. a good provider gives you one hostname and port that never moves, and the rotation happens invisibly behind it. if your code talks to the gateway instead of a raw IP, a carrier rotation does not break your session at all.

cause 2: rotation set too aggressively

a lot of providers, and a lot of users, set the IP to rotate every thirty or sixty seconds. for a single quick request that is fine. for a login, a checkout, or any multi-step flow, it is fatal, because the IP changes halfway through and the site sees a session that teleported to a new address.

the fix is a sticky session with a duration long enough to finish your task. set the sticky time to cover your whole flow, a few minutes at least, and rotate only when you choose to, not on a timer that fires mid-transaction.

cause 3: the SIM re-registering with the tower

this is a real, brief disconnect, and it is physical. when a phone hands off between cells, or the signal dips, or the tower drops and reacquires the radio, the data connection blinks for a second or two. on a real mobile network this happens occasionally and it is unavoidable, because it is a real radio on a real tower.

the fix is on your side: your code needs to retry once on a dropped connection instead of crashing. one automatic retry with a short wait absorbs almost every tower blip. if a single dropped request kills your whole run, the problem is that your code assumed a perfect connection, which no real mobile connection ever is.

cause 4: too many threads through one device

a single mobile proxy is one phone with one radio. if you fire forty parallel threads through it, you are asking one handset to behave like a server, and it will start refusing or dropping connections. this looks exactly like an unstable proxy when it is actually you overloading one device.

the fix is to cap your concurrency per IP. for a single mobile proxy, keep it to a handful of parallel connections, not dozens. if you need more throughput, you need more devices, not more threads through one.

cause 5: protocol and keepalive mismatch

mobile connections have higher latency than datacenter connections, anywhere from eighty to three hundred and fifty milliseconds, and they need their connections kept alive deliberately. a lot of “disconnects” are just a client timeout firing too early on a connection that was about to respond.

three settings fix most of this:

use socks5h instead of socks5, so DNS resolves through the proxy and not your local machine. plain socks5 leaks your local DNS and causes a whole class of stalls.
set a TCP keepalive so idle connections do not get silently reaped.
give your requests a real timeout, fifteen to thirty seconds, not the three-second timeout that works on a datacenter proxy.

here is what that looks like in Python with requests:

import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

PROXY = "socks5h://user:pass@sg.example-proxy.net:10000"  # socks5h = remote DNS

session = requests.Session()
# one automatic retry absorbs a tower blip instead of crashing the run
retries = Retry(total=1, backoff_factor=2, status_forcelist=[502, 503, 504])
session.mount("https://", HTTPAdapter(max_retries=retries))
session.proxies.update({"http": PROXY, "https": PROXY})

# 30s timeout gives mobile latency room to breathe (not a 3s datacenter timeout)
resp = session.get("https://ipinfo.io/json", timeout=30)
print(resp.json().get("ip"), resp.json().get("org"))

cause 6: carrier NAT idle timeout

this one catches people who hold connections open and quiet. carrier NAT tables drop entries that go idle. if you open a connection, sit silent for a couple of minutes, then try to use it again, it may already be gone on the carrier side, and you see a dead socket.

the fix is a heartbeat. send a small keepalive request every thirty to sixty seconds on a long-lived connection so the NAT entry stays warm. this is the cause behind a lot of disconnects that only happen after a pause in activity.

cause 7: the target site is dropping you, not the proxy

this is the one people never suspect. when you scrape too fast or trip a bot-detection rule, many sites do not return a clean error. they just drop the connection, reset it, or let it hang until it times out. from your side that looks identical to a flaky proxy, so you blame the proxy and switch providers, and the new one does the same thing, because the proxy was never the problem.

the fix is to slow down, add realistic delays between requests, and rotate to a fresh IP when you actually get blocked, not on a blind timer. the tell: if the disconnects only happen on one specific site and never on a neutral test like ipinfo.io, the site is dropping you, not the proxy.

cause 8: an oversubscribed or throttled provider

on a cheap shared plan, one IP is shared across many users, and when the device gets overloaded or another user on it gets it throttled, your connection suffers for reasons you cannot see or control. some providers also throttle or cut your session quietly once you cross a bandwidth threshold they do not advertise.

the fix here is structural: a dedicated device that nobody else is touching, and a plan where you know exactly what happens at the cap. if the disconnects are random, frequent, and you have ruled out the other seven causes, the provider is the cause.

the diagnosis order

run these in sequence, not at random. the order is the whole point.

log the IP on every request and decide: rotation or a real drop. if the IP changes but requests succeed, switch to a stable gateway endpoint and a sticky session, and you are done.
if it is a real drop, test against a neutral endpoint like ipinfo.io in a tight loop. if that is stable but your target keeps dropping, the target is blocking you, so slow down and back off.
check your concurrency. pull it down to a few threads per IP and see if the drops stop.
fix your client: socks5h, TCP keepalive, a thirty-second timeout, one automatic retry, and a heartbeat on idle connections.
only after all of that, if it is still dropping on a neutral endpoint at low concurrency with a clean client, the provider or the plan is the problem, and you move to a dedicated device.

what is actually normal

not every change is a problem to fix. a mobile IP that rotates is healthy. that is the entire reason mobile proxies work: the address keeps moving the way real subscriber traffic does. a small amount of rotation and the occasional one-second tower blip are signs you are on a real carrier network, not a static datacenter IP pretending to be mobile. if you are choosing between carrier generations for stability, 5G mobile proxies in Singapore covers what the radio actually changes.

the goal is not zero rotation. the goal is a connection that survives rotation cleanly, with a stable endpoint in front of it and a client that retries a blip instead of dying on it. fight the real disconnects and design around the normal ones.

the honest caveat

the right fix depends on which cause you have, which is why the diagnosis order matters more than any single setting. if you skip straight to blaming the provider and switch services, but your real problem was forty threads through one device or a three-second timeout, you will see the exact same disconnects on the new provider and conclude that all mobile proxies are unreliable. they are not. they are real radios on real towers, and they behave like it. once your client is built for that, a good mobile proxy on a dedicated device is stable enough to run multi-step flows and long jobs without babysitting.

if you have worked through all eight causes and want a dedicated device on a real Singapore carrier that holds a sticky session through a full flow, Singapore Mobile Proxy runs the hardware. start a trial at the Singapore Mobile Proxy home page.