Right-click in the preview window and lower preview resolution and/or frame rate. May help. Allow time for the green line, above the preview window, to complete.
Be sure there's ample free space on the that 1TB SSD.
If source files are very large, check out this process, which can smooth and speed previewing, especially on lower-end PCs.
Video editing is resource intensive. See how your CPU stacks up against I7-class NVidia processors.