As of January 14, 2019 at 3:00 p.m. PST, some customers were unable to install apps that contained Incoming Webhooks. We made a code change that inadvertently affected the list of available channels, preventing installation. At 5:35 p.m. PST, we made an additional code change to resurface this list and re-enable the installation process. We determined that this was resolved at 5:51 p.m. PST.
7:43 PM PST
For those affected, we're happy to report that the list of channels are appearing once again when attempting to install apps with Incoming Webhooks. Our apologies for keeping you away from your work.
6:01 PM PST
Customers will be unable to install apps with Incoming Webhooks, as there are no channels appearing in the installation drop-down menu. We're currently investigating, and we'll keep you posted. We're sorry for the trouble.
4:15 PM PST