Slack PowerUp stopped working: No more Slack Alerts are posted from Trello

[F_ Grimps]

Two weeks ago or so I have added the Slack PowerUp to one of my boards and integrated to Slack channels. Everything was working fine.

Yesterday, I added another Slack alert to the same Slack channel on another board. This was working as well. However, since today none of the alerts are working.

I checked the setup of the Slack PowerUp and notices all show a yellow warn sign stating:
Unable to post alerts because channel cannot be found.

I removed all alerts and tried to add one of the alerts back but the error persists.

What else I can do?

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I just noticed the integration is working when I use the Send to Slack channel function on an individual Trello card. But the Slack alerts feature is broken.

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I tried a few more things and found out the Alerts still worked on public channels.

Then I revoked the Slack/Trello integration on both sides and added everything back. Nothing is working now, and I can only select to send alerts to individuals instead of channels. This results in the new error message: Ran into an unknown error posting alerts: no_board_access.

There is clearly something going on behind the curtain. API changes on one/both of the sides, or something?

[Vida Popovic · Accepted solution]

Inviting Trello app again to private Slack channels via the command "/invite @Alen" seems to fix problems and brings back the alerts.

[Kensuke Suzuki]

Thanks!  It did solve my issue of "Unable to post alerts because channel cannot be found."

[F_ Grimps]

Thank you. Right on! 

In the end I had to reset and setup the Trello integration in Slack to make it work

• First, try /invite @@trell on the channels where Trello should be working.
• If that doesn’t solve the issue, try /trello reset followed by /trello setup
• Finally, if that doesn’t solve the issue, please remove the Slack Power-Up and personal settings from the board menu, and then re-enable the integration from a fresh start.

[Darian James]

Does any one else have any suggestions here? I've tried inviting Trello into the Slack channel and revoking permissions and reinstalling the PowerUp but i'm still getting the same error as Nicole above.

No longer authorized to post alerts on behalf of the creator.

Can someone help, this is a serious issue for our company as we rely on the Slack notifications to monitor accounts. 

[F_ Grimps]

Not an answer. I think you should ask a separate question and open a support ticket.

[Nicole McCulloch]

Don't have an answer, but noticed this happening as well today. The message I am getting is: No longer authorized to post alerts on behalf of the creator.

Help!

[F_ Grimps]

This error message is different from mine. Maybe this is still related to the same issue. I am going to revoke the integration on both sides and see if this fixes things.