Sorry. What I meant by "unsolicited" is the popup occurred without your permission.
One way you could get popups is from your browser. Also, your previous screenshots indicate that you are using Firefox. If so, Firefox blocks popups by default, that is, unless you didn't changed the setting. Popups can come from malware on your system too. A screenshot would help identify whether the popup came from your browser and that is the reason I asked for one.
Does one always get viruses or malware or spyware by solocitation?
No. No person in their right mind should intentionally "solicit" malware onto their system. However, since you did see a popup it could mean that you have malware on your system. It follows that you should be asking yourself... "Why did I get this popup?" "Do I have malware on my system?" "Should I get a check to see whether I have malware on my system?" ... and so on and so forth.