The panel uses its own small certificate authority (CA). Install the CA once on each device; after that the device trusts the HTTPS address like any web site, and the panel can be installed as an app.

Downloading the file is not enough: it must be installed as a trusted root authority, as described below. Until then the browser keeps saying "Not secure".

Windows

Quickest: download papaswitch-ca.crt, then in the Downloads folder run (no administrator rights needed):

certutil -user -addstore Root papaswitch-ca.crt

Windows asks for confirmation: answer Yes. Then close every browser window and open it again.

Or with the wizard:

1. Open papaswitch-ca.crt → Install Certificate → Current User → Next.
2. Choose Place all certificates in the following store → Browse → Trusted Root Certification Authorities → OK → Next → Finish → Yes.
   Do not leave "Automatically select the certificate store": it puts the certificate among the intermediate authorities, and the browser keeps saying "Not secure".
3. Close every browser window and open it again.
4. Firefox keeps its own list: Settings → Privacy & Security → Certificates → View Certificates → Authorities → Import → tick "Trust this CA to identify websites".

Android

1. Download papaswitch-ca.crt. Opening it from the download bar is usually not enough on recent Android versions.
2. Settings → Security (or Security & privacy) → More security settings → Encryption & credentials → Install a certificate → CA certificate → Install anyway → pick papaswitch-ca.crt from Downloads. Menu names vary a little by brand; search the settings for "CA certificate".
3. Close Chrome completely (from the recent apps) and open it again.

iPhone and iPad

1. Open this page in Safari and download papaswitch-ca.mobileconfig; allow the download.
2. Settings → Profile Downloaded → Install (enter the passcode).
3. Settings → General → About → Certificate Trust Settings → turn on PapaSwitch CA. Without this last step the certificate is installed but not trusted.

macOS

1. Download papaswitch-ca.pem and open it: Keychain Access adds it to the login keychain.
2. Double-click PapaSwitch CA → Trust → When using this certificate: Always Trust. Close the window and confirm with your password.

Linux

Download papaswitch-ca.pem, then:

sudo cp papaswitch-ca.pem /usr/local/share/ca-certificates/papaswitch-ca.crt
sudo update-ca-certificates

Chrome and Firefox on Linux may use their own lists: import the file in their certificate settings, under Authorities.

Still "Not secure"?

• "Certificate is valid" but still "Not secure": before installing the CA you clicked Advanced → Proceed (unsafe). The browser remembers that exception for the whole session and keeps marking the site as not secure (and will not offer to install the app). Restart it completely: type chrome://restart (Edge: edge://restart) in the address bar. To check without restarting, open the HTTPS address in a private/incognito window: it should show the padlock.
• The browser was not restarted after installing: close all its windows (Chrome and Edge often keep running in the background; use the restart address above).
• The certificate went into the wrong store (Windows: intermediate instead of root). Run the certutil command above.
• An old PapaSwitch certificate is installed (e.g. from another computer or folder): the fingerprint in the device's certificate details must match the one above.
• The address is not covered by the certificate (e.g. a name added to the router's DNS): use the IP address, or the names listed in SETUP → HTTPS CERTIFICATE.