The system that your old project runs on is being retired at the end of this year. It is now known as Blynk Legacy, and the Blynk Legacy servers are being turned-off on 31st December 2022.
In preparation for this, the Blynk Legacy apps have been removed from the App/Play stores.
Blynk has launched a new product to replace Legacy, known as Blynk IoT.
Blynk IoT uses different servers, and there is no connection between Blynk IoT and Blynk Legacy accounts, so if you try to log-in to the Blynk IoT system then it won’t recognise you unless you have created an IoT account.
There is no system for importing your Legacy projects into Blynk IoT, you will need to create an IoT account and manually set-up your projects again.
Your Legacy sketches will also need some changes to work with IoT, but these changes may be quite minor.
More info here…
Pete.