@Rita sometimes snap can be set to a smaller value if editing small details of a symbol. However forgetting to set the snap to original value leads to off-grid schematics. When in doubt, after setting SNAP to the default value (10) select the schematic and align to the grid. (Tools->Align to grid). Check the schematic to verify all devices are correctly connected, and make corrections if needed. Off grid placements are viral, if you copy-paste them they remain off grid and propagate everywhere :-)