Excel Solver - variables not changing or solution not correct

Hi

I am trying to solve an equation using Excel Solver. I am new to this function and have been self teaching but I think I'm at an impasse and looking for some help.

In the attached file there are 9 variables in row 2 - these are what I am looking to solve. The formula is in column E. It is the variables multiplied by a value + the next variable multiplied by the next value....

Like so....OA = (CON*A)+(TAL*B)+(EXP*C)....

I Know the values for OA, CON, TAL, as these are in the data set. I am trying to calculate A, B, C... I know most of the variables (H2:O2) are between 0.05 and 0.20 and that the variable in R2 is between -0.05 and -0.20.

So Far I have tried using solver to find a value of 0 when we subtract the calculated OA using my formula from the actual OA. I believe this should work in theory but solver is saying it has a solution and that solution doesn't end up being close to 0. I have tried different solving methods and I understand the solution is linear so mainly trying the LP Simplex engine with constraints added but either the solution isn't near 0 or the variable values don't change.

Please let me know your thoughts and / or any other information that could help you help me