I'm getting a "Not licensed" or "Paused (exceeds license limitation of x sensors)" message for a number of sensors I added to the configuration. However, I have not reached the sensor limit for my license. How do I go about fixing this?

This article applies to PRTG Network Monitor 16.4.28 or later

Sensors Showing "Not Licensed" Message

PRTG Network Monitor is licensed on a 'per sensor' basis, meaning that the license does not limit monitoring to a number of devices. Due to this license mechanism it is possible that under circumstances PRTG Network Monitor will display a "Not Licensed" message. This article explains what to check and do if parts of your sensors in PRTG Network Monitor display a blue status icon and show 'Not Licensed'.

First of all, open Setup | License from the main menu bar in the PRTG web interface. The fields of interest are License Status and Licensed Edition.

Note: In older PRTG versions, you can find according information under "Setup | PRTG Status | System Status" or "System | PRTG Status | System Status". Look for the fields "Edition" and "Activation Status" in section "Licensing".

Freeware Edition (License key already in use)

If you find Freeware Edition (License key already in use) or a similar message in the edition field, then PRTG detected another instance of PRTG running with the same license key in your network (which is only allowed for PRTG XL5/Unlimited licenses).

Deactivate the license on the second instance to revert it to a freeware edition or uninstall it after license deactivation. Then restart the PRTG services of your original PRTG installation.

Note: In older PRTG version you might have to enter a freeware or trial license key for the odd instance to stop running it as commercial edition. Use the PRTG Administration Tool (or PRTG Server Administrator) for this purpose.

Freeware Edition (Activation Grace Period Expired)

If you are running a commercial version and the program reports Freeware Edition (Activation Grace Period Expired), check under Setup | License from within PRTG. Please be aware that PRTG Network Monitor needs to be activated within 10 days (this is the 'Activation Grace Period') after the initial installation on a machine. As such, if you haven't activated, please try to do so using the automatic mechanism or, if this fails, use the manual activation option.

For details, see PRTG Manual: License Information.

Other Cases of 'Not Licensed' Sensors: Paused (exceeds license limitation of x sensors)

Most other cases with sensors showing a Not Licensed status are caused by exceeding the limit of licensed sensors. If the number of current used sensors exceeds the number of licensed sensors, all sensors above that limit will be paused automatically with the status Not licensed. In such an instance, please consider an upgrade to a higher edition of PRTG.

You can look up the number of used sensors under Setup | PRTG Status, section Database Objects, in the PRTG web interface and compare this number with your licensed edition.