Now you go to storage tab and select the datastore, then go to configure tab -> general and presss the increase button.
Normally you shouldbe able to extend the datastore.
I've seen such issues with some recent vSphere versions, independent of the storage array used.
What helped was to run vmkfstools -V (not the upper case "V") on all hosts to rescan the storage.
You may want to run the command again on all hosts after increasing the datastore.
I encountered the same issues and now I could expand the disk. Thank you so much for your help
