Safari 12 temporarily doesn’t support the WiseStamp extension. This is already in the works and should be fixed by the first week of October 2018.
What can you do now?
1 – You can work on Chrome, where the extension works flawlessly.
2 – If you use Gmail, you can go to the no-extension flow.
We apologize for the inconvenience – and will update this article when this issue has been resolved!