Alright, there is no code and environment configuration information here. We don't know the actual situation.
From your description, I understand that you can only have 3 connections in IIS on Windows. and Why it works with Express but it doesn't with the non-Express. Assuming there is nothing wrong with debugging. IIS has very low connection limits on non-server operating systems. This is a limit set by the Windows licensing team. Windows Server OS doesn't have these request restrictions. But IIS express does not have requests restrictions. You can refer to IIS Request Restrictions on Windows Client OS according to your device. Alright, about IIS concurrent connections you can refer to this: https://topic.alibabacloud.com/a/number-of-font-colorrediisfont-connections-font-colorrediisfont-concurrent-connections-font-colorrediisfont-maximum-concurrent-worker-threads-application-pool-queue-length-application-pool_8_8_30350250.html.
I found you posted the same on Stack Overflow, I'll follow you on the Q&A forum.
Best Regard,
TengFei Xie
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