Hi @hasaka0110 ,
You can try the following solutions, refer to: How to Fix HTTP ERROR 500 in ECP/EAC after Login
1.Use a Different Browser (Chrome or Firefox)
2.Install Pending Server Updates (If there is an update)
3.Reinstall Updates
4.Improved resource allocation (CPU and Hard Disk Space)
5.Update Server Configurations
6.Recreate Virtual Directories
7.Repair Exchange Server
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