Germany has refused Trump’s request to help defend Strait of Hormuz: This is not NATO war

The German government has rejected U.S. President Donald Trump’s request to participate in an operation to reopen the Strait of Hormuz.
This was stated by German government spokesperson Stefan Cornelius, according to Censor.NET, citing n-tv.
Details
"This war has nothing to do with NATO. It is not a NATO war," he said.
According to the spokesperson, NATO is an alliance for the defense of its territory and has no mandate for NATO deployment in this conflict.
What led up to this?
Trump had previously stated that NATO could face a "very bleak" future if its allies did not help to reopen the Strait of Hormuz.