When I was truing to upload images to products in the Magento admin panel I got the following error:
SSL Error: Invalid or self-signed certificate while uploading image from backend

The way I solved this issue was by setting the timezone on the computer that I was uploading from to the same timezone as the settings in Magento.

Other suggestions to try out if that don’t work:

• If you are using certificate: Verify that it is valid, you have correct domains etc
• Set use secure url in admin to false