Hi Avila, it can be not so good to make objects thousands of units across. If you scale down your object to a more regular size that can help.

To do that, select your object and run the Transform > Scale command.

At the first prompt where it says "Pick origin point" type 0 and push Enter, that will specify 0,0,0 as the scale origin.

Then at the next prompt type in 0.01 and push enter and that will scale your object to 1/100 of its original size.

You can then select that edge and put a fillet on of 0.07 units and it seems to be ok.

- Michael