I've done both these courses online in the last year - found them very good. The first one is a cert, and the second one is a diploma. The cert is pretty easy, and very interesting to do. Took me about two months to complete.
The diploma on medicinal cannabis and cbd oils with centre of excellence took me about six months to complete and was a more comprehensive course covering the entire ECS, the plant, and a lot of biology.
https://www.coursera.org/learn/medical-cannabis-pain-control (Certificate in Medical Cannabis and pain control)
https://www.centreofexcellence.com/ref/register?ref=14d1fb3f822e136 (Medicinal Cannabis & CBD oil)