Hi,
For anyone having this issue in the future I found the answer. Older versions are no longer able to to online activate and will have to be painstakingly activated offline. I suppose they want us to upgrade. Hopefully this saves you lots of time searching why your username and password aren't working when trying to activate online.
Legacy activations:
Studio One 4: https://support.presonus.com/hc/en-us/articles/360043921991--3-Studio-One-5-Software-Activation-Online-Computer-
Studio One 1, 2 and 3: Online activations of Studio One versions 1, 2, and 3 are no longer supported. To activate these dated versions of Studio One, you will need to do an offline activation. Below is a link to an article from our knowledge base with instructions.
https://support.presonus.com/hc/en-us/articles/360043922251--4-Studio-One-5-Software-Activation-Offline-Computer-
Please be aware, since the release of Studio One 6, Studio One versions 1, 2, 3 and 4 are no longer supported. The current supported versions of Studio One are versions 5 and 6.
For legacy support information, you can always use one of the following resources.
1. Our Knowledge Base located at https://support.presonus.com/hc/en-us
2. Our forum located at https://forums.presonus.com/
3. The Studio One Facebook Group: https://www.facebook.com/groups/presonusstudioone/
4. Our Newest Community Forum at http://answers.presonus.com/
5. If you would like to upgrade to Studio One 6, here is a link: https://shop.presonus.com/Studio-One-Upgrades-Crossgrades