SolPress Is Finished
After heavy speculation surrounding the company, it is now – given the status of Sol Press, LLC – official that the company's days are almost certainly numbered.
While the common phrase everyone says in response to what happened is simply that they've not payed their taxes, the exact status for the company is: "FTB FORFEITED". This status indicator is more than a simply "they've not payed their taxes," though one might argue it is perhaps sufficient as a response to the question. It specifically means that they've either failed to "file a return," or "pay taxes/penalties/fees/interest."
In either case, while Sol Press didn't have the most impressive range of light novels and manga, they did have a few titles that were of interest. More specifically:
Light Novels
- I Surrendered My Sword for a New Life
- Let This Grieving Soul Retire! Woe is the Weakling Who Leads the Strongest Party
- Saving 80,000 Gold in Another World for my Retirement
- The Game Master has Logged In to Another World
Manga
- Is the Order a Rabbit?
- Blend S
Let's just hope that some other publisher manages to "rescue" these titles from the dreaded licensing hell.
Update
A news post by A*N (Archive.org link) has shed some light on the situation.
Also, turns out the CEO is a piece of garbage who just up and vanished, only to buy and play weird simulator games on Steam instead:

References
businesssearch.sos.ca.gov. (2021). Business Search - Business Entities - Business Programs | California Secretary of State. [online] Available at: https://businesssearch.sos.ca.gov/CBS/SearchResults?filing=&SearchType=LPLLC&SearchCriteria=Sol+Press&SearchSubType=Keyword [Accessed 3 Nov. 2021].
Ca.gov. (2021). My business is suspended | FTB.ca.gov. [online] Available at: https://www.ftb.ca.gov/help/business/my-business-is-suspended.html [Accessed 3 Nov. 2021].
Wikipedia. (2021). Sol Press. [online] Available at: https://en.wikipedia.org/w/index.php?title=Sol_Press&oldid=1049111755 [Accessed 3 Nov. 2021].