Blizzard has shut down the trading system in Diablo 4 for the time being due to an exploit that players were using to farm massive amounts of gold.
Unfortunately, this means that trading is suspended for all players, not just those using the exploit. There is currently no other way to trade items with other players.
Here is everything we know about the situation and when we could see the trading suspension lifted from Diablo 4 Season 1.
Why Can’t I Trade in Diablo 4 Season 1?

Blizzard suspended player trading in Diablo 4 on August 14, 2023, due to a gold and item duplication exploit that players were using. They did not give a time frame for when trading would return but promised they are working on a fix to mend the issue quickly.
Some players suspected that trading would return with the Patch 1.1.2 Update on August 15, but that was not the case. Blizzard did provide an update saying that trade functionality is still in review.
The exploit itself required players to initiate a trade with another player, drop the items or gold in the trade slot, and then force the Diablo 4 client to close. That same player would then log back in and have their items or gold reappear in their inventory while the other player also kept the items.

It basically allowed players to duplicate items with each other, which is a clear breach of Blizzard’s End User License Agreement and damaging to the Diablo 4 economy.
Any player that used this trading exploit will likely have their account banned as Blizzard continues to investigate the issue if they haven’t already. However, they also confirmed that they have a way of knowing when someone used this trading exploit accidentally.
Players shouldn’t worry about receiving an accidental ban during this situation, even if they are constantly trading with other players. Only those who used the exploit willing will receive an account ban.