There are three errors in the event log always together when this happens:
--------------------------------------------------------------------------------------
[ Name] DynamicPDF Converter
Keywords 0x80000000000000
[ SystemTime] 2021-11-01T20:08:42.620153400Z
Service stopped. Exception details Type : System.InvalidCastException Message : Unable to cast object of type 'SyncStream' to type 'System.IO.MemoryStream'. Source : DynamicPDF.Converter.Service StackTrace : at d.c() at g.a(d A_0) at g.e() at g.b() at System.Threading.ThreadHelper.ThreadStart_Context(Object state) at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx) at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state) at System.Threading.ThreadHelper.ThreadStart()
--------------------------------------------------------------------------------------
[ Name] .NET Runtime
Keywords 0x80000000000000
[ SystemTime] 2021-11-01T20:08:42.621159700Z
Application: DynamicPDF.Converter.Service.exe Framework Version: v4.0.30319 Description: The process was terminated due to an unhandled exception. Exception Info: System.InvalidCastException at d.c() at g.a(d) at g.e() at g.b() at System.Threading.ThreadHelper.ThreadStart_Context(System.Object) at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean) at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object) at System.Threading.ThreadHelper.ThreadStart()
--------------------------------------------------------------------------------------
[ Name] Application Error
Keywords 0x80000000000000
[ SystemTime] 2021-11-01T20:08:43.013147200Z
DynamicPDF.Converter.Service.exe
3.10.0.44688
6142ebbe
KERNELBASE.dll
10.0.17763.2183
12a65345
e0434352
001235e2
2664
01d7cf5bca5aa128
c:\Program Files\DynamicPDFService\DPDFConverterService\DynamicPDF.Converter.Service.exe
C:\Windows\System32\KERNELBASE.dll
c8268568-da22-42c2-8da6-6c8f4d3b6d49