Then in the app's Hootsuite stream, click the Manage Authentication button under the settings menu, and then click the Delete Authentication button in the Instagram section of the popup which is displayed.
Re-authenticate on Facebook. (you will be prompted to do so, in the Synapview app's stream) During the re-authentication process, Facebook will ask you which Facebook pages/Instagram accounts you want to give Synapview access to. If you do not see a particular account there, you do not have access to it, and will have to ask the owner of the Facebook page associated with the Instagram account to give you access to the page and Instagram account. After you have done that, re-authenticate with Facebook once again.