Support

What to do when error -3 appears during license activation?

Updated on 16 September 2026 tcpGPS Leer en español

Error -3 displays the message “Server response error. Please contact our technical support.”

This is a connectivity error, as the application does not receive a response from the license server. You can follow the procedure below for activation:

No stable connection: If there is no stable connection, a data packet may have been lost along the way, causing the application to consider the activation invalid. Try connecting to a different WiFi network or enabling and using mobile data.
Connection restrictions or Firewall: If your internet connection has restrictions (common in corporate or public organization WiFi networks), the device may be unable to contact the license server. In these cases, it is recommended to:
1. Try a different or less restricted WiFi network (such as a home network).
2. Use a mobile data connection.
3. Create a hotspot connection from another mobile device using its mobile data, and connect the application's device to it.

NETWORK REQUIREMENT FOR AUTOMATIC ACTIVATION AND TRANSFER

In addition to having an Internet connection, the computer must be able to connect to Aplitop's license server https://licenses.aplitop.com on port 443 (TCP/HTTPS).

This connection is essential to register or activate a standalone (single-seat) license (LDK software key) for the first time, and to transfer a license, both on the computer releasing it and on the computer receiving it.

The domain, Active Directory policies (GPO), the perimeter or local firewall, the proxy server and any SSL inspection systems must explicitly allow this outbound connection on every computer involved. If error -3 occurs on a company network, this is the first thing to check with the IT manager. Full technical details are available in Network requirements to activate or transfer a license.

This requirement does not apply to network licenses managed by a license server. If your IT department cannot authorize this outbound connection, use the offline (manual) method:

In MDT: 3.5 SOFTWARE KEY (OFFLINE ACTIVATION) - MDT26 for activation, and 5.2 SOFTWARE LICENSE TRANSFER (MANUAL) - MDT26 for the transfer.
In PCE: 3.3 Manual Software License Activation - PCE.

If the problem persists after ensuring a stable connection, it is recommended to contact technical support at Aplitop. Surveying and Civil Engineering Software by going to Support > Support Centre and sending a support form, attaching a screenshot of the error and describing it.