Clear DNS servers

I’m looking at NextDNS DNS on RouterOS and on the NextDNS page, it has this command to clear any existing servers:

/ip dns set servers=

Except it doesn’t seem to work. What’s the correct syntax to clear any existing DNS server entries? This works to set it:

/ip dns set server=1.1.1.1

Sorted… bit more Googling found: /ip dns set servers=“”