Mosaicing of two scenes

I have a problem with the Mosaicing Operator. When I try to combine two adjacent scenes the resulting product hast a much coarser resolution then the original scenes.
What could be the mistake I am making?

original S1 scene


Thank you!

which tool did you use for mosaicing? SNAP has several ways to do it

I used Mosaicing from Raster -> Geometric Operations

“SAR-Mosaic” is working!

But now I have a problem with batch processing.
I have multiple scenes from different dates and want to mosaic two of them so that they cover my study area, which is in between two scenes.
I tried to batch process them, but “Find-Image-Pair” gives an error. I tried different min and max days apart values.