I created my first Nami wallet, after which I tried to look up my address in Cardano Explorer but it comes up as non-existent. What problem could it be? Can resetting the wallet be a solution?
If the address did not receive any ADA up to now, explorers cannot know that the address is part of an existing wallet.
There is no registration of wallets or addresses on the blockchain. Explorers can just observe, which addresses appeared in transactions. Once an address receives its first ADA, it will also appear in explorers.