> For the complete documentation index, see [llms.txt](https://launcher-docs.netmarble.com/faq-en/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://launcher-docs.netmarble.com/faq-en/launcher-download/5.md).

# An 'unknown error (api)' message appears when downloading the launcher installer

This issue occurs when your PC's network environment (firewall, proxy settings, etc.) blocks the download of the launcher installation file. Please refer to the details below to resolve the issue.

1. Temporarily disable your antivirus program and try again.
2. If you are using a firewall or proxy, please check that Netmarble addresses (\*.netmarble.com) are not blocked.
3. If a certificate issue is suspected, please refer to the certificate check and installation steps in the \[['Server delay' notice](/faq-en/launcher-launch/8.md)] article.
4. If the issue persists, you can download the installation file directly from your browser using the links below.
   * Epic Netmarble Launcher: <https://ntiny.link/launcher_download_epic>
   * GPG Netmarble Launcher: <https://ntiny.link/launcher_download_gpg>
   * Netmarble Launcher: <https://ntiny.link/launcher_download>

* If the download does not work in your browser either, access is being blocked by your network environment itself, so please check your network settings.
* If the unknown error occurred while running the launcher, please refer to the \[[Unknown error alert](/faq-en/launcher-launch/3.md)] article.
* If the problem persists, please contact Customer Support.