MAMP Pro (MacOS) host can't connect using https.. "Error code: SEC_ERROR_UNKNOWN_ISSUER "

Question

I am trying to configure one localhost using MAMP Pro (6.x) on MacOS. The SSL checkbox is also yes but when I load the site, it shows "Error code: SEC_ERROR_UNKNOWN_ISSUER" in the Firefox and same error in console of Chrome. Attached are the error screenshots from Chrome, Firefox and localhost settings from MAMP Pro.

Stack info

• MAMP Pro 6.x.
• Mac OS Monterey
• WordPress (siturl and homeurl in DB are using https. wp-config.php forcing https too)
• hostname: movecn.dev

What I tried till now?

• Tried Self-signed certificate
• Tried ports (80, 443, 8890)

Answer 1

I figured it after spending hours and hours. MAMP / MAMP pro creates "MAMP_PRO_Root_CA" which suppose to be added and trusted in MACos keychain. It will be used to sign all the future/custom SSL certs.

In my case, "MAMP_PRO_Root_CA" was already added in the keychain but it was not trusted by the system. Steps to resolve.

• Open Keychain Access and click "System Root" left side
• Click "Certificates" on the top and then search for "MAMP_PRO_Root_CA" select and click "Get info"
• In Trust section/dropdown, choose "always trust"
• close it. (It may ask for your password etc)
• Close and restart your browser.