Repository Health Check: maven-central' [healthcheck] execution failure

Hi,
I’m having trouble with a 403 Forbidden error in health check.
Looking at the log, I’m getting the following exception.
Not only the maven-central but also the reference to another internal repository is the same error.
I also set up HTTP and HTTPS proxy settings correctly.
The result of the curl command is also returned.

Is there any other possible cause?

Thank you

[log]
2021-12-09 14:15:48,492+0900 INFO [quartz-9-thread-20] *SYSTEM org.sonatype.nexus.scheduling.TaskSchedulerImpl - Task ‘System - Repository Health Check: maven-central’ [healthcheck] scheduled: hourly
2021-12-09 14:15:48,493+0900 WARN [quartz-9-thread-20] *SYSTEM org.sonatype.nexus.quartz.internal.task.QuartzTaskJob - Task b7fae7ea-abdb-4a8b-bdfd-5291db2d8dce : ‘System - Repository Health Check: maven-central’ [healthch
eck] execution failure
java.io.IOException: Failed to determine health check interval for repository maven-central, status code 403 Forbidden
at com.sonatype.nexus.plugins.healthcheck.task.HealthCheckTask.doDeltaCheck(HealthCheckTask.java:246)
at com.sonatype.nexus.plugins.healthcheck.task.HealthCheckTask.doRunSafe(HealthCheckTask.java:139)
at com.sonatype.nexus.plugins.healthcheck.task.HealthCheckTask.execute(HealthCheckTask.java:102)
at com.sonatype.nexus.plugins.healthcheck.task.HealthCheckTask.execute(HealthCheckTask.java:1)
at org.sonatype.nexus.scheduling.TaskSupport.call(TaskSupport.java:100)
at org.sonatype.nexus.quartz.internal.task.QuartzTaskJob.doExecute(QuartzTaskJob.java:143)
at org.sonatype.nexus.quartz.internal.task.QuartzTaskJob.execute(QuartzTaskJob.java:106)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.sonatype.nexus.quartz.internal.QuartzThreadPool.lambda$0(QuartzThreadPool.java:145)
at org.sonatype.nexus.thread.internal.MDCAwareRunnable.run(MDCAwareRunnable.java:40)
at org.apache.shiro.subject.support.SubjectRunnable.doRun(SubjectRunnable.java:120)
at org.apache.shiro.subject.support.SubjectRunnable.run(SubjectRunnable.java:108)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

It is self-solving.

This is not a problem in Nexus.
The problem with our environment was that we couldn’t access to ‘https://rhc-pro.sonatype.com’.