It is due to the processor and graphics being under recommended specs. Trying to run games on a computer that has less than recommended specs can cause crashes and other issues.
Laptops with U processors (example: i7-8550U) aren't designed to play games. They're an office/school type of laptop made for daily tasks, not so much gaming. -- Ultra-low-voltage processors are a class of microprocessor that are deliberately underclocked to use less power at the expense of performance. Plus lack the adequate cooling laptops need when playing games.
The graphics GT940MX has been known to cause crashing with games.
Your desktop may run the game better due to having a better processor, and graphics. What you may want to try is to see if you can clear some files and/or programs off the desktop to help with running Sims 4. Also, if it's not to old, you may want to consider adding more memory to it to help it run the game better.
Some things to try with the laptop are:
1. Deactivate Origin in Game -- Open Origin, Select Origin > Application Settings > Origin In Game and deselect or turn Off to disable Origin In Game.
2. If you have a dual graphics card system, make sure the game runs on the card and not the chip.
http://sims4.crinrict.com/en/2014/09/graphics-cardintel-chip-dual-systems/3. Try running Origin As Administrator - Right-click on the Origin icon on the desktop and select Run as Administrator.
4. Try playing the game in "Offline" mode -- In the Origin Client, go to the Origin Menu and select Go Offline.
5. Start the game in Windowed mode -- In the Origin Client, go to the Games Library tab, and right click on the Sims 4 Cover and select Game Properties - In the Command Line Arguments, add the following text: -w and click Okay. If this doesn't work, try: -w und
Read more troubleshooting tips in the post linked below:
Crashing Issues/Stopped Working
http://www.carls-sims-4-guide.com/forum/index.php?topic=29308.msg408903#msg408903
