[gmx-users] Inconsistency in user group

[Amir Zeb]

Hello GMX users,

I want to compute the distance between COM of two residues's side chains by
gmx distance option.
When I'm specifying the first group from the selection menu as one residue
and 2nd group as 2nd residue, I'm getting the following error

Inconsistency in user input:
Selection 'A_MT218' does not evaluate into an even number of positions
(there
are 11 positions)

Can anyone please help me for possible solution of this issue?

Thanks in advance!