The fact that the OP did not originally say they were using Mint seems not very relevant. They are using Mint, and this is most likely the cause of the answer not working, so the question is off-topic.
If it is any good it can be migrated:
Good off topic questions: migrate rather than close?
If you feel we need that question here for Ubuntu, not Mint, then perhaps consider making a Q&A.
Leaving a question like this by a Mint user here is just asking for trouble imho - OP could accept an answer that happens to work for Mint but not Ubuntu, downvote an answer that DOES work for Ubuntu because it doesn't work for them, etc. The OP has a lot of control over the post. We shouldn't sweep under the rug that they are using another distro - it's too risky.
Edit: On reflection, while I still think the edit was right (to explain OP's situation & behaviour) and the question should be closed (to avoid setting a precedent & the risk of answers that don't work for Ubuntu being added & accepted), since you already answered it for Ubuntu perfectly well, and you don't want to make a Q&A, I think it's fine to leave the question here, not migrate it, and make sure it doesn't get deleted, since it's useful to Ubuntu users...