[Observium] Problem with Status Summary (Port down)

Hello,

I have a little problem. In the status summary on the frontpage one port listed as down:

[cid:image001.png@01D27BE4.30D4AD50]

If I click on the "1 down" I don't see any port listed:

[cid:image002.png@01D27BE4.30D4AD50]

Is this a bug? How can I get rid of this last remaining port in the summary?

Thanks Siegfried