Solver returen error and cannot solve, and did close the file

You have set to many constraints and trying to solve this excel uses so much RAM capacity, it fell flat on its feet.

When setting up solver use as few constraints as possible, run solver. If it works, fine. You then can add more constraints.

I've deleted constraints AI4:AI9 and I also set calculation to automatic. Solver now runs ok. But this solution is not maximized i.e.
as total capacity cell P10 sums up to only 3124287,5 but total line capacity is 3232805.

Looking at the numbers in P4 to P9 you will see that P5 and P6 is not up to maximum capacity so you need to relax the constraint you set on the range W10 to AH10.

Alf