On the left (in blue) you have used blocks of the Simscape Foundation Library.
On the right (in black) you have used blocks of the Simscape Electrical Specialized Power Systems library.
Unfortunately, you cannot mix and match blocks from both libraries.
I suggest you only use blocks of the Simscape Foundation Library, or all categories under the Simscape Electrical library, apart from the Specialized Power Systems.
The two blocks you want to use on the right-hand side, can also be found in the library outside Specialized Power Systems.
- Resistor: Simscape - Foundation Library - Electrical - Electrical Elements
- Voltage measurement: Simscape - Foundation Library - Electrical - Electrical Sensors
For some specific use-cases it is interesting to use the Specialized Power Systems library, but especially if you want to add other physical domains the other blocks are the way to go.
You may also want to read my answer to this other question: https://nl.mathworks.com/matlabcentral/answers/462756-why-are-there-multiple-models-of-same-device
