Sum of array elements - program freezes (Easy68K)

I am trying to write a program in Easy68K to calculate the sum of the elements of an array, but it freezes at ( screen of the error ).

Maybe I didn't fully understand how a0, (a0), and the sum work. Could someone help me?

Here is my code:

            ORG $8000
            
array DC 1,2,3,4,5,6,7,8,9,10  ; DC reserves 4 bytes for each element  
                                ; $8000 -> 1, $8004 -> 2, etc.
len EQU 10                     ; Number of elements in the array
sum DC 0                       ; Variable to store the sum

START:  
      suba.l a0,a0              ; Clear register A0 (set to 0)
      clr d1                    
      clr d0                    
      movea array,a0            ; Load the address of 'array' into A0
      move len,d1               
      move sum,d0               

LOOP:
     TST d1                     ; Check if D1 (counter) is zero
     beq END                    ; If zero, exit the loop
     
     move (a0),d5               ; Load the value at address A0 into D5
     add d5,d0                  ; Add D5 to D0 (accumulate sum)
     addq #4,a0                 ; Move to the next element in the array (4-byte step)
     subq #1,d1                 ; Decrease the loop counter by 1
     bra LOOP                   
  
END: 

    SIMHALT                      

    END     START

Solution

array DC 1,2,3,4,5,6,7,8,9,10  ; DC reserves 4 bytes for each element

Don't omit the size specifier from your directives and instructions! From the screenshot it is clear that a naked DC reserves just a 2-byte word and not the 4 bytes that you claim and use thoughout your program.

suba.l a0,a0              ; Clear register A0 (set to 0)
clr d1                    
clr d0

No need for clearing these if you're going to assign them in full.

move (a0),d5               ; Load the value at address A0 into D5
add d5,d0                  ; Add D5 to D0 (accumulate sum)
addq #4,a0                 ; Move to the next element in the array (4-byte step)

There's no need for a separate increment of the address register. 68k has the "post-increment" addressing mode that does that automatically:

move.l (a0)+, d5   ; Load the value at address A0 into D5
add.l  d5,d0       ; Add D5 to D0 (accumulate sum)

This code should work:

ORG $8000

array DC.l 1,2,3,4,5,6,7,8,9,10 ; DC.l reserves 4 bytes for each element
len   EQU 10                    ; Number of elements in the array
sum   DC.l 0                    ; Variable to store the sum

START:
  movea.l array, a0             ; Load the address of 'array' into A0
  move.b  len, d1
  clr.l   d0
LOOP:
  add.l   (a0)+, d0             ; Add longword at A0 to D0, and post-increment A0 by 4
  subq.b  #1, d1                ; Decrease the loop counter by 1
  bne.s   LOOP
  move.l  d0, sum               ; Copy to memory-based variable (should it be needed)
  SIMHALT
  END START

The power of the 68000 lies in its ability to do many things together in a single instruction. add.l (a0)+, d0 will add the longword at the address A0 to D0 and then raise the contents of A0 by the size of the operation (longword means 4).
Avoid loops that have a mere bra in the end. Always try to 'conditionally' jump to the top of the loop.