Moving site from one droplet of digitalocean to another droplet

[asnair]

My site has been running in a droplet of digitalocean (DO) with Centos and Zpanel. Now I am moving the site to another droplet with Ubuntu and Sentora. 

I have set up the domains and DNS in Sentora in the new Ubuntu droplet (same as in the working zpanel in Centos droplet. Thus the domain added in the droplet with Sentora is the same as in the old site. Both the droplets are powered on.

My site is continuing to run from the old site (with the old IP address). My doubts are under:-

a) Do I have to power-off the old droplet for the propagation of the domain name to the new droplet (with a new IP address)? (I would like to avoid this, as my site would be down for a few hours at least while the domain propagation is complete)

b) If I keep both the droplets powered on, then will propagation of domain take place for the new IP address? When that happens will the domain name automatically start to direct traffic to the new IP address?

c) If not so, what is the least painful option available to me? Any suggestions?

[asnair]

I feel the DNS is not propagating because the domain name entered while installing Sentora (in the DO droplet) was wrongly typed by me.
How can I correct the domain name as originally entered while installing Sentora?

[asnair]

I have solved the problem I described as above. This was due to a stupid mistake on my part. I had misspelt the domain name at the A record at Digitalocean. Now DNS propagation is happening as expected. Problem solved.

Now I have a new problem! I am unable to delete the wrong domain name that I had entered in Sentora. When I click "delete" in Sentora against the domain name, the page refreshes, but the domain name does not get deleted; and there is no error message.

What could be wrong?

Any way I am closing this issue as closed and raising a new issue for not being able to delete domain at Sentora