LT1763-1.8 wrong output voltage

Hello,

     I want to use the LT1763IS8-1.8 chip to convert +5V to 1.8V. The schematic and PCB are as follows, but in the actual circuit, the output of the 1-pin is measured by a multimeter to be 2.1V, and the +5V input is also reduced to 4.5V. Why, what should I do.

Thanking you.

With best regards and wishes.