The optical delay creates a null signal. If the input to the component has, for example, 5 separate signals, then the delay should be set to 5 (in order to create 5 separate null signals).
If the 32 users are combined into a single transmission channel (one signal) then the delay only needs to be set to 1 (the default value).
I suggest running the design with the delay set to 1 at all locations to see if the design converges. Alternatively, all the delays can be removed from the design, and within Global Parameters/Signals the “Initial delay” check box can be selected and the number of “Iterations” can be set to, for example, 10.