ABP throws an exception at the back end

throw new UserFriendlyException($"report an error");

Before publishing, you need to set whether to send an error to the front end
if this is set to true, all exceptions and details will be sent directly to the client in case of an error. Default value: false (ABP hides the exception details from the client, except for special exceptions.)

public override void PreInitialize()
{
    Configuration.Modules.AbpWebCommon().SendAllExceptionsToClients = false;
    #if DEBUG
    Configuration.Modules.AbpWebCommon().SendAllExceptionsToClients = true;
    #endif
}