Error de instalación del certificado SSL de Go Daddy en el servidor D.O.

I did the free let’s encrypt option and got mixed SSL browser error. After inspecting, it says this:

Mixed Content: The page at ‘https://portal.slccpoa.org/’ was loaded over HTTPS, but requested an insecure image ‘http://portal.slccpoa.org/uploads/default/original/1X/be8d1b2f999b51c2c7895046e80485ac288492fb.jpeg’. This content should also be served over HTTPS.

Can you guide me in how to fix this?

Thanks