Direct message to Slack user with whitespace in their Slack name

[Ben Briggs]

Greetings - I have a Trello board which allows people to submit requests for work to be done. The card uses a custom field to capture the requestor's Slack address. I set up a rule to notify the requestor of progress on their request using the Slack Power Up. The custom field is "Requestor Slack Name" so the Trello rule sends the message to {{%Requestor Slack Name}}.

This all works fine for anyone with a Slack display name with no whitespace characters in it (i.e. @Ben) but fails for people with spaces in their Slack names (i.e. @Ben Briggs). Any suggestions on how to get around this? I did try "@Ben%20Briggs" but had no luck with that.

Thanks.

[Ben Briggs]

Never mind, I found the answer. As I suspected, the "Display name" is not the Slack ID you need to use. There is a hard-to-find 9-digit Slack ID that needs to be used for this purpose. It appears that the Slack display name will work in some cases, but not consistently.