It seems that Sentris Network will close all their free VPS, offers which started in 2017. I think this has something to do with OpenVZ 6. I received the following e-mail.
Hi We're just letting you know that if you still using our old Free VPS OpenVZ server, it is time to upgrade for free. If you don't already have a new OpenVZ 7 VPS for free, we suggest you go to our site and do so now - https://freeserver.us. This old server will be closed down in 2 weeks, by end of this month. If you sign up for our Free plan but cannot apply the coupon, please reply to below forum with your username, do NOT post your IP Address there. https://sentris.net/billing/forum/80/oldopenvzserver.html We will then actiuvate your account. You do need to signup first. Any questions, please post to above forum for help. Do NOT contact us directly! As doing so will result in immediate termination of your free vps account. We thank for all these years using our service. Sentris Team.