Cloudways should allow the swap files. This was, less memory servers can be used with traffic which is just above 512mb server to handle.
Please see comment.
AdminCloudways (Admin, Cloudways) commented
Servers already have a 256MB swap file. We have configured swap in our servers in a way to ensure performance is not affected. Swap will kick in only to avoid processes been killed in out of memory situations (OOM killer). This has proved extremely effective for 512MB servers stability.