Setting the solver properly

I do not understand exactly what or how you are trying to optimize this. If I may request clarification:

3. Variables are in D18:D26 -- Does this mean that you want these to be your "By changing" cells? I note that changing these cells has no impact on L18:L25 (which you claim is your objective function or your "Set Target Cell" -- did I misunderstand?), so it would seem impossible to maximize L26 if there is no relationship between D18:D26 and L26. Are there supposed to be formulas that connect these cells?
4. I did not understand at all how O18:O26 fits into your model and optimization.

Among the things I see:

A18:A25 are blank (which Solver will interpret as 0) is this your best guess for a starting value? I would probably try your upper or lower bounds (C49:C56 or F49:F56) or something in the middle (all =0.5).
Trying upper and lower bounds shows that the lower bounds will be out of range for other criteria, and seems to represent a minimum. The upper bound values seem to be a maximum and most constraints are met. Is Solver even needed if the upper bound is the maximum? Are there scenarios where the upper bound is not the maximum?

I note that, as presently programmed, H48 is always "-", because D26 always evaluates to an error due to the text string in A26. I don't know what this constraint represents, nor what the computation in D26 is supposed to be, but something does not seem right here. Perhaps this is the main source of your difficulty -- getting an appropriate non-error expression in D26.

Once all of the constraints are being calculated correctly, it seems like the Solver model should be:
Set target cell: C26
To a maximum
By changing: A18:A25
Subject to the constraints as listed.