The Resolver Record
The Resolver field for an ENS name is normally set to the ENS Public Resolver contract which helps resolve your ENS name into usable records like wallet addresses, avatars, etc. You can update records in the ENS App, as long as you are using the ENS Public Resolver.
This is similar to how DNS helps resolve regular domain names into usable records like IP addresses.
There are a wide variety of records that can be set and resolved depending on your use case.
Some examples are:
Wallet address records
Contains records about your various wallet addresses, so that funds can be sent to them.Avatar record
Contains a link to an image stored as an NFT or on a website and used to visually represent your ENS name.Social links
Useful links to, for example, your GitHub, LinkedIn, or Twitter profiles.
Without a resolver record set, ENS records are not possible.
ENS Public Resolver
If your resolver is unset or you've changed it, you can set it back to the default ENS Public Resolver in the ENS App. Go to the More tab of your name, then click Edit under the Resolver section, then select 'Use latest resolver' and confirm the transaction onchain.
The new ENS Public Resolver contract:
0x231b0Ee14048e9dCcD1d247744d114a4EB5E8E63
The old ENS Public Resolver contract:
0x4976fb03C32e5B8cfe2b6cCB31c09Ba78EBaBa41
the old ENS Public Resolver contract will continue to work and should not cause any issues.