We have confirmed the following issue.
We ask for your patience as we proceed with investigations and a resolution.

[Confirmed Issue]

■The item, “Silver Rivets” that is required to make “Wooden Showcase” cannot be obtained.

* We are planning to make another recipe for it in patch 4.41.

We apologize for the inconvenience, and thank you for your patience and understanding.

*Update Oct. 2, 2018 4:00 a.m. (PDT) / 11:00 (GMT) / 12:00 (BST):
This issue was addressed in the maintenance which occurred from Oct. 1, 2018 11:00 p.m. to Oct. 2, 2018 2:15 a.m. (PDT) / Oct. 2, 2018 6:00 to 09:15 (GMT) / Oct. 2, 2018 7:00 to 10:15 (BST).
The recipe for the "Wooden Showcase" furnishing has been altered with this fix.
We apologize for any inconvenience this may have caused.