> For the complete documentation index, see [llms.txt](https://docs.portainer.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.portainer.io/faqs/licensing/why-isnt-my-3-license-key-working.md).

# Why isn’t my 3- license key working?

When attempting to enter your license key into Portainer Business Edition, that starts with 3-, you may encounter the following error message:

`License is invalid`

#### Cause

This issue arises when using versions of Portainer 2.18.3 or older. These previous versions do not support the 3- license key type.

#### Fix

To resolve this problem, upgrade your Portainer version to 2.18.4 or newer.\
[Upgrade instructions](/start/upgrade.md)