Cannot connect to NTRIP caster — what now?

NTRIP corrections travel over a standard internet connection. If your device cannot reach the internet, it cannot reach the NTRIP server — regardless of how correctly everything else is configured.

• 1
  Open a browser on the same device and navigate to any website. If it does not load, resolve the connectivity issue before proceeding.
• 2
  If using a receiver with a built-in SIM card (Emlid RS3, RS4, some Trimble units), verify the SIM has an active data plan and signal bars are showing.
• 3
  If using a phone hotspot, check that the device connecting to the hotspot actually has internet access through it — not just a Wi-Fi connection to the hotspot.
• 4
  In areas with weak cellular signal, switch between 4G and 3G modes. A stable 3G connection is better than an unstable 4G one for NTRIP streaming.

NTRIP uses TCP port 2101. Some corporate Wi-Fi networks and mobile carriers block outbound connections on non-standard ports. If you have general internet access but cannot reach the NTRIP server, port blocking is likely.

• 1
  Switch networks. If on corporate Wi-Fi, switch to mobile data. If on mobile data, try a different carrier's SIM or a Wi-Fi network at home.
• 2
  Use a personal hotspot. Create a hotspot from your phone's mobile data connection and connect your field device to it. This bypasses most corporate network restrictions.
• 3
  Ask IT to open the port. On a corporate network, request that TCP port 2101 outbound is opened for your device. This is a standard NTRIP requirement.
• 4
  Test the port directly. On a computer, open a terminal and run telnet ntrip.rtksub.com 2101. If the connection opens, the port is accessible. If it times out, the port is blocked.

If the server is reachable but your client receives an error like 401 Unauthorized or 404 Not Found, the problem is credentials or mountpoint name.

• 1
  Check for typos. Username and password are case-sensitive. Copy and paste from your service confirmation email rather than typing manually.
• 2
  Load the sourcetable. Most NTRIP clients have a "Get Mountpoints" or "Source Table" button. Use it to fetch the current list of available mountpoints from the server — do not type the mountpoint name manually.
• 3
  Check your subscription status. If your trial or subscription has expired, the server will reject your credentials even though they look correct.
• 4
  Verify the host address. Do not include http:// or https:// before the hostname. Enter the hostname only — for example ntrip.rtksub.com — and set the port separately to 2101.

VRS (Virtual Reference Station) mountpoints require your rover to send its approximate position to the NTRIP server. The server uses this to generate a virtual correction point near you. If GGA is not sent, the server streams nothing — you are connected but receive 0 bytes per second.

• 1
  In your NTRIP client settings, look for options labelled Send GGA to caster, Transmit NMEA GGA or Send position to server. Enable it.
• 2
  Make sure your receiver has at least a Single solution before connecting. GGA requires a valid position — even a rough one. If GGA contains all zeros the server cannot generate corrections.
• 3
  If you are not using VRS but still seeing 0 bytes, try switching to a non-VRS mountpoint such as RTCM3_NL. Standard mountpoints do not require GGA.