After a few days of troubleshooting, Senior Game Producer Tom Ellis posted an announcement on X, formerly Twitter, stating that the auction house performance should be significantly improved for players!
Maintenance Plans with Auction House
There were a variety of player reports in regards to issues with auction house performance over the last few days. Operations were slow across the board: putting up orders, buying out items, getting mail, etc. In the most latest update, Tom Ellis stated that the Auction House performance should be significantly improved for now! Most operations of the auction house should be back up and running efficiently. In a reply, Tom also stated that temporary throttles have been removed and developers will continue to monitor. Additional maintenance is still planned for the future.
Further background was also provided in a discussion with Community Manager Kaivax over on the Blizzard Forums.