You should be able to login with the same account from Vaishnava.com on any of the other new sub domains. If you encounter your email already in use because it's registered on Vaishnava.com or you are experiencing some errors please notify us asap and we will fix the issue.
There was a previous announcement on the old Forum on Vaishyamart/Vaishnava.com about having a completely new name from Vaishyamart to Vaishnava.com. And there were dates when this occured. Here are the dates: April 16th-29th, 2019.
Vaishnava.com is also known as "Vaishnava Marketspace" or just "Vaishnava". The forum is moved but the threads are lost.
Just to inform you if you don't already know, Vaishnava.com is currently on Beta. What this means is the website is still undergoing development. The site is functional. Feel free to shop or open up your own store but just be aware that you may run into errors or bugs.
In any case, you can report the bug or error in this forum Support > Bugs & Errors or you can submit a request at the Help Center.
Vaishnava.com will continue with a series of new designs. Expect some beauty changes!