Galvanic Relay

• WOTC Official Reminder Textofficial rules
  Storm — When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.

• WWizards of the Coast2021-06-18
  Official Ruling
  You can play the exiled card only on your next turn after Galvanic Relay resolves. Notably, this means you cannot play it the same turn you cast Galvanic Relay.
• WWizards of the Coast2021-06-18
  Official Ruling
  Playing the card has the same timing restrictions and requires the same payments as normal, but it can only be played next turn.

Rulings via Scryfall

• WO
  Wizards of the Coast2022-03-07

  Galvanic Relay was banned in pauper on March 7, 2022. No public reasoning provided. Source: https://magic.wizards.com/en/news/news/march-7-2022-banned-and-restricted-announcement
• WO
  Wizards of the Coast2022-03-07

  Galvanic Relay was banned in pauper on March 7, 2022. After the ban of Chatterstorm, Galvanic Relay was a powerhouse without a strong enough home. However, the introduction of Experimental Synthesizer in Kamigawa: Neon Dynasty (especially when backed by Deadly Dispute) was the missing piece to reopen this can of worms, leading Black-Red Storm to climb to the top of the format with a 60% win rate. Source: https://magic.wizards.com/en/news/news/explanation-pauper-bans-march-7-2022