Hi Baris, so a big complication there is your edges are running into other spots where you've already created fillets previously, like here:





There's also a similar situation at the bottom as well.

When you have fillets that are going to run into each other it's much better to do all the edges for them at the same time instead of in different passes. When you do them in pieces the edges from the previous ones are now part of your object and the new fillets will have to try and deal with them as well. When you do them all together the filleter is better able to know how to stop fillets that are running into each other and build a corner juncture patch where they meet up.

Also doing ones that run into each other in bits makes for more complicated selection - if you have a sequence of edges that meet up smoothly, you can't just select a single edge from that sequence and try to fillet it because that would cause a hole to open up in your model. Here I've made an example with an enlarged fillet to help illustrate:





So if just that edge is selected and not the additional edge that's been created above it from previous filleting, you're basically asking the filleter to do something like this which opens up a hole:



The filleter doesn't like to do that. You'd need to also select the edge from the previous fillet so it could try to run a fillet all the way to the top without opening up a hole. But additionally if this new fillet is of the same radius as the previous one, the little fillet piece that will run to the top can be difficult to create, it's trying to do it as a fillet surface built between 2 previous fillets. And it can cause particular difficulty if the fillets are very small.

It's much better to do all the fillets of the same radius that run into each other all at once instead of separately, that will allow it to make a corner juncture patch between them like this:


Having a corner juncture patch usually makes things much better for the filleting engine, it knows that it can stop the fillet surfaces before they run into each other and it also knows that it can be constructed using a piece of a sphere. If it tries to create fillet surfaces going between existing fillet surfaces of the same radius, with the whole thing collapsing down to a point, that's a lot more complications.

Hope this makes sense - on those notched areas you have it's ok to do one of those separately as long as you do the entire notch, but if you're doing the longer vertical edges you don't want to have done the top or bottom separately, do them all at the same time. And if you have different radius values being used you usually want to put in the largest radius ones first and the smaller ones last.

- Michael