Portfolio Vulnerabilities is not updated anymore

### Current Behavior:
On the main dashboard "Portfolio Vulnerabilities" last update is one month old.

The refresh button is not changing anything.

In the logs, I can see the server is trying to update the portfolio but I don't any success :
2022-05-03 23:42:51,600 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 00:43:37,880 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 01:44:27,953 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 02:45:16,859 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 03:46:09,899 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 04:47:03,863 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 05:47:49,725 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update
2022-05-04 06:48:39,061 [] INFO [org.dependencytrack.tasks.MetricsUpdateTask] Executing portfolio metrics update

### Steps to Reproduce:

I don't know.

### Expected Behavior:

I would like to have the portfolio up to date.

### Environment:

- Dependency-Track Version: 4.4.2