I took a look at your image and see that you have a custom thing called conversation with a field marked task that you are trying to relate to.
you need to make sure that the field you are saying equals mailbox hash is an identical type. In this case text. Take a look at the images I have posted below to gain a better understanding of whats going on. However what I believe you need to do is simply say "Task = "Do a search for… " “Tasks” then in the filter options select “unique id” and say = mailbox hash.
Also note that if you are using the mailbox hash to store more then the unique id you will need to use either find and replace / extract with regex or any combination of the two to filter the value you need from the entire string of text.
Also not to discourage you but working with API’s without a solid understanding of how bubble deals with data, lists vs single values etc can be difficult and will be an uphill battle. It wont take long but if you have other features that need building that do not require an api it would be better to start there and come back to this after, you’ll have answered a lot of your own questions by then.
