I notice that I couldn't insert images when adding products in tinymce content part.
When I click on Insert Image button, I saw error as image below
I granted access to
/media directory 777.
I followed the instruction Magento 2.3.0 "A technical problem with the server created an error." When uploading the logo image but it did not fix issue. I checked
var/log/system.log but the log did not show any text errors.