I was able to contact phone support today, who stated that 401 and 601 are billing errors and that I should try contacting my bank. After stating that I contacted my bank, the rep asked if I still had free trial time and stated that I wouldn't be able to set a sub until that time expires. When I asked about the 401 error when trying to upgrade, the rep stated that this maybe the case because I tried the same payment method a few times and that I should give it a week before trying again as they have a locking system in place that will enforce a 24h lock on payments after a failed attempted and if tried repeatedly will add an other 24h lock.It was also suggested that I use a different card but that isn't really an option. Anyway I'm going to speak with my bank again and retry the upgrade in a week or so and see what happens.