@Helzi Hi. If you’re using a legacy version of macOSX (anything below 10.12) I’m afraid you are experiencing an incompatibility issue where one of the plugins used is not working properly. Unfortunately this is an ongoing problem we’re trying to address. If you want more detail please read a previous reply on a similar topic: Version 0.6.4 Will not export animation file to anything
A temporary solution would be to downgrade to a previous version only for export. Here’s the link to version 0.6.4 https://github.com/pencil2d/pencil/releases/tag/v0.6.4
That said if you are using a recent version of macOS, please let us know if you’re using also the latest version of Pencil2D since it could be a different issue.