@PRajShar To clarify what this error is trying to say: Let's assume that you have an existing website app (i.e external to Cloudron) on
app.domain.com. Now, you go to Cloudron and try to install an app in the domain
app.domain.com. Cloudron will detect that the DNS already has an entry for this and fail with the above error. To fix this, go to your DNS provider and remove the
app.domain.comentry. Then in Cloudron, click the Repair (wrench icon) and it should work.
Alternately, just use another subdomain app2.domain.com or something.