Connection Troubleshooting

Disconnection issues after iOS / macOS 26 update

This page is for you if you have these symptoms
  • Connects but drops within a few minutes
  • Disconnects automatically after a short use
  • Even when switching servers, each only connects once and soon drops
  • Rebooting the router or checking the internet does not help
  • It was stable until a few days ago and then suddenly changed

This is mostly reported by iPhone (iOS 26.x) or Mac (macOS 26.x) users.

What causes this?

Apple's latest OS updates (macOS 26.4.1 / iOS 26.4.2) changed IKEv2 VPN behavior. If an old IKEv2 profile remains on the device, automatic re-negotiation fails every 1-2 hours and the connection drops.

This is not a problem on our server side.
Only users with the matching OS version + old profile combination are affected. Other OS users continue to use the service normally at the same time.

Applying just step 1 or 2 below resolves the issue immediately.

How to fix
1Switch the protocol in the app to OpenVPN (fastest fix)
  • Open the TitanVPN app -> Select the protocol on the main screen OpenVPN
  • OpenVPN is not affected by Apple's OS update.
  • Check that the connection becomes stable. If it is, you are done.
SSTP or V2RAY protocols are equally stable. Choose the one that suits your environment. SSTP V2RAY
2Uninstall and reinstall the app (simple method)
  • Fully delete the TitanVPN app -> Reinstall from the App Store
  • Deleting the app usually removes the bundled VPN profile automatically.
  • After reinstalling and reconnecting, you will start cleanly with a new profile.
  • If this does not work, proceed to step 3 below.
3Manually delete the IKEv2 profile and certificate, then reconnect (root fix)

If reinstalling does not solve it, an old profile or certificate is still on the system. Please remove it manually with the steps below.

For iPhone / iPad

  1. Settings -> General -> VPN & Device Management
  2. Tap all VPN entries named "TitanVPN" or similar -> Delete
  3. If certificates or configuration profiles exist under "Profiles", delete those too
  4. Fully quit the TitanVPN app, reopen it -> Connect -> Allow installing the new profile

For Mac (macOS)

  1. System Settings -> VPN
  2. Select the "TitanVPN" entry -> click the right ⓘ or "−" button -> Remove configuration
  3. Open "Keychain Access" -> search for "titan" or "ikev2" -> delete all related certificates and keys
  4. Quit the TitanVPN app, reopen, and connect
4Quit the app, wait 5 seconds, then relaunch
  • If you retry immediately after a drop, the app cycles through other servers automatically, which can make things less stable.
  • Fully quit the app -> wait about 5 seconds -> try to connect just once
5Check that the app is the latest version
VPN connects but no Internet (MTU fix)

If your VPN shows as connected but web pages will not load, and turning the VPN off restores the Internet, the cause is almost always an MTU mismatch. This is especially likely if your other devices (same account) work normally.

Why does this happen?
On some ISP, hotel, or public Wi-Fi networks, the default VPN tunnel MTU of 1500 gets fragmented and silently dropped. Each OS handles auto-adjustment differently, so the problem may appear only on Mac or Windows.

Please follow the steps for your OS below. iOS and Android are generally not affected.

macOS
1Open Terminal
  • Launchpad → Other → Terminal (or search "Terminal" in Spotlight)
2Identify the exact VPN tunnel interface

Mac may have several utun interfaces active at once (utun0, utun1, utun2, utun3 — iCloud Private Relay, Sidecar, etc.), so you must pick the one carrying VPN traffic. With the VPN connected, paste the command below into Terminal and press Enter:

ifconfig | awk '/^utun[0-9]+:/{i=$1} /inet 10\./{print i,$2}'

Sample output: "utun3: 10.14.132.64" — the part before the colon is the interface name (utun3), and the part after is the private IP assigned by the VPN server. Remember this utun name exactly.

If you see multiple lines, the rows whose inet address starts with 10.8.x / 10.14.x / 10.20.x / 10.170.x belong to our VPN. Lines starting with 100.64.x or 198.18.x are Apple Private Relay — ignore them.
If nothing prints, the VPN is not actually connected — reconnect from the app and try again.
3Try MTU 1380 → 1280 → 1200 in order

Admin password required. Replace utun3 with your actual interface name from above. (1) Try 1380 first:

sudo ifconfig utun3 mtu 1380

Open google.com / naver.com in your browser to verify. If it works, you are done.

(2) If 1380 still does not work, try 1280:

sudo ifconfig utun3 mtu 1280

(3) If still no luck, lower it to 1200:

sudo ifconfig utun3 mtu 1200

Usually 1380 or 1280 fixes it. If even 1200 does not work, MTU is not the cause — go to "Switch to OpenVPN" below.

Note
This is a temporary setting. When you disconnect and reconnect the VPN, the utun number may change and the MTU resets to 1500, so you must run step 2 (find interface) and step 3 (set MTU) every time you connect.
A permanent fix will be included in the next app update.
Windows
1Open Command Prompt as Administrator
  • Search "cmd" in the Start menu → right-click → "Run as administrator"
2Identify the exact VPN adapter name

Windows also has multiple interfaces at the same time (Ethernet, Wi-Fi, virtual adapters), so you must identify the exact VPN adapter name first. With the VPN connected, paste this command into cmd and press Enter:

netsh interface ipv4 show subinterface

In the output table, find the row where State=connected and the Interface column matches "TitanVPN" or your VPN connection name. IKEv2 is usually "TitanVPN"; OpenVPN is usually "TAP-Windows Adapter".

Interfaces named "Ethernet", "Wi-Fi", or "Local Area Connection" are NOT the VPN. Never set MTU on those — it will break your normal Internet.
3Try MTU 1380 → 1280 → 1200 in order

In the command below, replace only the "TitanVPN" part with the exact adapter name you found above. (1) Try 1380 first:

netsh interface ipv4 set subinterface "TitanVPN" mtu=1380 store=persistent

Disconnect and reconnect the VPN once, then verify in your browser.

(2) If 1380 still does not work, try 1280:

netsh interface ipv4 set subinterface "TitanVPN" mtu=1280 store=persistent

(3) If still no luck, lower it to 1200:

netsh interface ipv4 set subinterface "TitanVPN" mtu=1200 store=persistent

Thanks to store=persistent, Windows keeps this setting permanently after a single configuration — no need to re-run it each time.

This is most common on hotel or public Wi-Fi. If it works fine at home or the office but fails only when you are out, MTU is almost certainly the cause.
If it still does not work
Switch to OpenVPN
  • In the Titan app, change the protocol to OpenVPN 으로 변경
  • OpenVPN handles MTU internally, so it is stable without the above setting.
  • SSTP is also less affected, for the same reason. SSTP
If it still does not work
  • If you exceed the simultaneous connection limit (usually 2-4 devices), the oldest device is dropped automatically when a new one connects. Please check how many devices are using your account at the same time.
  • On hotel or public Wi-Fi, MTU differences may cause some sites to fail to load or frequent disconnections. In that case, please switch to OpenVPN.
  • If none of the above resolves your issue, please contact us via KakaoTalk channel or Telegram for individual diagnosis.
What to include when you contact us
(1) Device used (iPhone / Mac / Windows / Android)
(2) OS version (e.g., iOS 26.4.2, macOS 26.4.1)
(3) App version in use
(4) Approximate date when the disconnections started