sqm fails for some molecules

[ricardojdgferreira]

Hi Dev,

after an extensive debugging, I found that when sqm fails for some molecules (without warning, only get issues from packmol because the coordinates are empty), but unfortunately I cannot track where the problem is.
I have seem the same questions regarding openff-toolbox (probably it comes from there).
Any ideas to make the package more "verbose" (in order to debug it)?

NOTE: with smaller molecules it almost never fails.

UPDATE: it seems that sqm is not the real culprit, but packmol instead. After debugging wiht PDB, I managed to isolate the problem in which packmol failed to place the molecule inside the box. That said, by increasing the "box_scale_factor" under setup.py to 1.15 the error disappears.
Maybe some more info on errors would allow a faster debug of such problems.

Best!