Written for Synergy 3 (v3.8.4) and Synergy 1 (v1.22.3), checked 20 October 2026.
Find the message you see below; each one starts with what to do.
Offline activation
With an offline serial key:
- Start sharing, which brings up the request to activate:
- Synergy 3 shows Your license needs to be activated on this computer. when the primary computer starts sharing.
- Synergy 1 opens its Offline activation window when it starts as a server.
- Enter the Activation code on your account page from any device with internet access.
- Type the Response code you get back.
- Click Activate.
For the full steps, see: How license activation works
- That response code is not valid for this computer. Check you typed the whole response code, and that it was made from the activation code shown on this computer.
- A unique ID for this computer could not be determined, so an activation code cannot be generated. Please contact our support team.
Need help with any of these? See: Contacting our support team
What follows depends on your product: Synergy 3 or Synergy 1
Synergy 3
When there's something to do about your license, Synergy 3 shows a message instead of the settings. Most have an Apply new license button: click it, then log in or enter your new serial key. For the steps, see: Entering or changing your serial key
The messages about a license or maintenance period ending appear only with a Synergy Business license.
Your license will expire on ...
Renew your business subscription before then to avoid an interruption (or buy one, if you're on a trial), then click Apply new license and log in to fetch your new serial key. Click Continue to keep using Synergy 3 for now. How renewal works: Manage your Synergy Business subscription
Your license expired on ...
Renew your business subscription, or buy one if you were on a trial, then click Apply new license and log in to fetch your new serial key. Synergy 3 can't be used until you do.
Your maintenance period will expire on ..., or expired on ...
Synergy 3 keeps working: click Continue. Renewing your maintenance period keeps you getting updates and technical support. How to renew it: Manage your Synergy Business subscription
Your license is invalid.
Click Apply new license and enter a valid serial key from your account page.
This license has reached its activation limit.
Deactivate a computer you no longer use on your account page, or ask us to raise the limit at no extra cost, then click Try again. For the steps: How license activation works
The message may show a License reference to quote if you contact us. While it says Asking the license server again shortly., Synergy 3 is already trying again by itself.
A license was not found matching the serial key provided.
Click Apply new license and log in, or paste the serial key from your account page. The key Synergy 3 has doesn't match a license on our server, so it can't be activated.
Your license couldn't be activated because the license server didn't respond.
Sharing still works. Check this computer's internet connection, then click Try again, or click Continue to carry on for now. If this computer can't reach the internet, an offline serial key activates without it: How license activation works
Your license couldn't be activated because of an error.
Sharing still works. Click Try again, or Continue to carry on for now. If this keeps happening, please click Contact tech support on the message.
Messages when you log in or enter a serial key
For Invalid serial key. Please log in to your Synergy account to get the correct one., Invalid email address or password., Sorry, there are no valid licenses on your account. and Sorry, there was a problem logging in., see: Entering or changing your serial key
Sorry, there was a problem activating your license.
Click Activate again. If it keeps happening, please click Contact tech support on the message. Synergy 3 shows this under the Response code during offline activation, above.
Synergy 1
Synergy 1 asks for your serial key in its Serial key window, which opens by itself when there's something to do about your license. To open it yourself, choose License > Change serial key. For the steps, see: Entering or changing your serial key
The messages about a license or trial ending appear only with a Synergy Business subscription or trial.
License expiring soon
Renew your business subscription, or buy one if you're on a trial, then enter your new serial key in the Serial key window that opens after the message. Until then, click Cancel in that window to keep using Synergy 1. How renewal works: Manage your Synergy Business subscription
The message starts with Your license expires in a number of days, or Your trial ends in a number of days.
License expired
Renew your business subscription, or buy one after a trial, then enter your new serial key in the Serial key window that opens after the message. Synergy 1 stops working until you do.
The message starts with Your license has expired. or Your trial has ended.
You'll need to purchase a license to use Synergy.
Click Back and enter your serial key. Synergy 1 shows this when you click Cancel in the Serial key window without a valid key, and closes if you click Exit.
Serial key problem
Copy your serial key again from your account page and paste it in. Invalid serial key. Please contact us for help. means the key isn't complete or correct; Sorry, that serial key has expired. Please renew your license. means it's time to renew. More about these, and Write access required: Entering or changing your serial key
Activation failed
Follow the first line of the message:
- This license has reached its activation limit. Deactivate a computer you no longer use on your account page, or ask us to raise the limit, then click Start again.
- A license was not found matching the serial key provided. Click Change serial key and paste the key from your account page.
If you contact us, include the License reference shown in the message. How activation works: How license activation works