I pulled out my Amcrest IP2M-841 camera and did some testing and unfortunately it looks like they only provide support for embedding the username and password using a format which is no longer supported for embedding on Google Chrome and some other modern browsers. (eg. username:password@cameraURL)
I had my camera running through Blue Iris which can be used to consolidate multiple cameras into a single interface and acts as a nice DVR for your cameras. Blue Iris has URLs which work with SharpTools and that’s how I previously viewed these cameras in SharpTools.
If you don’t want to setup Blue Iris, another alternative would be to use TinyCam as a middle-man. Similar to Blue Iris, it can take the video from your camera as an input and then output in a format supported by SharpTools. You can find more details about using TinyCam as a middle-man in this post: Use TinyCam as a middle-man for incompatible camera streams