Hank here from Shopify.
When did you first notice this, or did you receive any error messages in your admin prior to the store going offline? Is the same message present when using incognito mode?
Or have you received an email from the accounts team at Shopify? If you had, my advice would be to respond directly to this email with any questions you may have, as they are best equipped to deal with any account queries. Note that sometimes emails will get sent to your junk/spam folder.
However, if you have not received an email, let me know, and I can look into this further for you.
All the best,
Thank you for the additional context.
I'd like to take a closer look at this for you, and as this is account specific, I will just need to verify your account. I will send you an email to the email address attached to this forum's account and confirm some security questions about your store.
Once you reply to that email, I will look into this further for you.