Why do I have abnormal termination due to "Access violation" during a Simulink simulation?

I am running on Simlink a simulation of a model, and I have after few minutes a message of 'access violation'. I try to continue simulating after the error, but it never stops (usually lasts 20 minutes, now hours and hours until I close matlab).

Compared to previous working version, I have added a huge legacy code* to read a C code, of 99 input and 8 outputs. Of course the Cntrl+D (update diagram) works. Below the error Log.

Have you an idea of why it happens?

I've run simulation with sim( ) command, without opening the model.

Thanks a lot

*https://www.mathworks.com/help/simulink/slref/legacy_code.html

******** ERROR LOG ********************************************

MATLAB crash file:C:\Users\pzjmqd\AppData\Local\Temp\matlab_crash_dump.21060-1:

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Access violation detected at Wed Nov 02 11:30:40 2022 +0100

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Configuration:

Crash Decoding : Disabled - No sandbox or build area path

Crash Mode : continue (default)

Default Encoding : windows-1252

Deployed : false

Graphics Driver : Intel Intel(R) UHD Graphics 620 Version 4.5.0 - Build 26.20.100.7757

Graphics card 1 : Intel Corporation ( 0x8086 ) Intel(R) UHD Graphics 620 Version 26.20.100.7757 (2020-1-9)

Java Version : Java 1.8.0_202-b08 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode

MATLAB Architecture : win64

MATLAB Entitlement ID : 4373313

MATLAB Root : C:\Apps\matlab2020a

MATLAB Version : 9.8.0.1721703 (R2020a) Update 7

OpenGL : hardware

Operating System : Microsoft Windows 10 Enterprise

Process ID : 21060

Processor ID : x86 Family 6 Model 142 Stepping 10, GenuineIntel

Session Key : 2c3f086b-a368-40b0-9856-************

Window System : Version 10.0 (Build 19044)

Fault Count: 1

Abnormal termination:

Access violation

Register State (from fault):

RAX = 000000006ecfbfe0 RBX = 00000187940bedb0

RCX = 00000187940c0bf0 RDX = 0000000000000000

RSP = 00000060b59f5420 RBP = 00000060b59f54a0

RSI = 00000187940c27ac RDI = 00000187940c28fc

R8 = 00000187940c1994 R9 = 0000018794096620

R10 = 00000187940c1d0c R11 = 00000187940bedb4

R12 = 00000187940c459e R13 = 0000018794096874

R14 = 0000018794096814 R15 = 00000187940c16d4

RIP = 000000006ecc1ff1 EFL = 00010202

CS = 0033 FS = 0053 GS = 002b

Stack Trace (from fault):

[ 0] 0x000000006ecc1ff1 C:\Users\...\Documents\ATTIVITA\MY_MODEL\LegacyCode_EDB3AA4A247561DA.mexw64+00008177

[ 1] 0x00007ffd5c9873b1 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15233969 slSetStateflowChartAccessesModelInfo+00198641

[ 2] 0x00007ffd5c986002 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15228930 slSetStateflowChartAccessesModelInfo+00193602

[ 3] 0x00007ffd5c98326c c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15217260 slSetStateflowChartAccessesModelInfo+00181932

[ 4] 0x00007ffd5c9896f8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15243000 slSetStateflowChartAccessesModelInfo+00207672

[ 5] 0x00007ffd5c95aa4a c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15051338 slSetStateflowChartAccessesModelInfo+00016010

[ 6] 0x00007ffd5c43cd3e c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+09686334 ouRequestBlockReduction+00185950

[ 7] 0x00007ffd5a0626b1 c:\apps\matlab2020a\bin\win64\sl_engine_classes.dll+03548849 ExecSystem::InitExecSystemScheme+00008433

[ 8] 0x00007ffd5af25d64 c:\apps\matlab2020a\bin\win64\sl_lang_blocks.dll+09067876 AlgLoopSubSysOutputTask::doWork+00002164

[ 9] 0x00007ffd5c0147af c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05326767 SLGlue::getGraphLines+00365087

[ 10] 0x00007ffd5c015bf8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05331960 SLGlue::getGraphLines+00370280

[ 11] 0x00007ffd5c5ae985 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+11200901 SlExecGraph::SLEEKDepChecker::walkBDAndFindDeps+00095429

[ 12] 0x00007ffe06bc6f0b C:\Apps\matlab2020a\toolbox\simulink\blocks\fcncallgen.mexw64+00028427 mwboost::serialization::singleton_module::lock+00002427

[ 13] 0x00007ffd5c9873b1 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15233969 slSetStateflowChartAccessesModelInfo+00198641

[ 14] 0x00007ffd5c983258 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15217240 slSetStateflowChartAccessesModelInfo+00181912

[ 15] 0x00007ffd5c9896f8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15243000 slSetStateflowChartAccessesModelInfo+00207672

[ 16] 0x00007ffd5c95aa4a c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15051338 slSetStateflowChartAccessesModelInfo+00016010

[ 17] 0x00007ffd5a0626b1 c:\apps\matlab2020a\bin\win64\sl_engine_classes.dll+03548849 ExecSystem::InitExecSystemScheme+00008433

[ 18] 0x00007ffd5af25d64 c:\apps\matlab2020a\bin\win64\sl_lang_blocks.dll+09067876 AlgLoopSubSysOutputTask::doWork+00002164

[ 19] 0x00007ffd5c0147af c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05326767 SLGlue::getGraphLines+00365087

[ 20] 0x00007ffd5c015bf8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05331960 SLGlue::getGraphLines+00370280

[ 21] 0x00007ffd5c5ae985 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+11200901 SlExecGraph::SLEEKDepChecker::walkBDAndFindDeps+00095429

[ 22] 0x00007ffe06bc6f0b C:\Apps\matlab2020a\toolbox\simulink\blocks\fcncallgen.mexw64+00028427 mwboost::serialization::singleton_module::lock+00002427

[ 23] 0x00007ffd5c9873b1 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15233969 slSetStateflowChartAccessesModelInfo+00198641

[ 24] 0x00007ffd5c983258 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15217240 slSetStateflowChartAccessesModelInfo+00181912

[ 25] 0x00007ffd5c9896f8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15243000 slSetStateflowChartAccessesModelInfo+00207672

[ 26] 0x00007ffd5c95aa4a c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+15051338 slSetStateflowChartAccessesModelInfo+00016010

[ 27] 0x00007ffd5a0626b1 c:\apps\matlab2020a\bin\win64\sl_engine_classes.dll+03548849 ExecSystem::InitExecSystemScheme+00008433

[ 28] 0x00007ffd5af25d64 c:\apps\matlab2020a\bin\win64\sl_lang_blocks.dll+09067876 AlgLoopSubSysOutputTask::doWork+00002164

[ 29] 0x00007ffd5c0147af c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05326767 SLGlue::getGraphLines+00365087

[ 30] 0x00007ffd5c015bf8 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+05331960 SLGlue::getGraphLines+00370280

[ 31] 0x00007ffd5c5ae985 c:\apps\matlab2020a\bin\win64\libmwsimulink.dll+11200901 SlExecGraph::SLEEKDepChecker::walkBDAndFindDeps+00095429

[ 32] 0x00007ffd38a0b090 c:\apps\matlab2020a\bin\win64\sf_runtime.dll+01159312 sf_call_output_fcn_call+00000096

[ 33] 0x000001874950153f <unknown-module>+00000000

[ 34] 0x00000186e9842ca0 <unknown-module>+00000000

[ 35] 0x0000018793b51230 <unknown-module>+00000000