API keys not saved on wordpress plugin

I have been trying to save the API key on my wordpress installation for quite some time now.
Despite of having done the following:

1. Clearing browser cache
2. Removing the cache plugin
3. Disabling all other plugins like Wordfence, Google Ananlytics etc.

The system does not allows saving the API key.
When looking at the Chrome Console it gives below error

Failed to load resource: the server responded with a status of 404 (Not Found)
compiled.js?ver=3.3.2:35 action USER_LOGIN @ 23:42:32.894
compiled.js?ver=3.3.2:35 POST http://ghoomleyaar.com/wp-admin/admin-ajax.php?action=cloudflare_proxy 500 (Internal Server Error)
d.end @ compiled.js?ver=3.3.2:35
o @ compiled.js?ver=3.3.2:35
a @ compiled.js?ver=3.3.2:35
i @ compiled.js?ver=3.3.2:30
(anonymous) @ compiled.js?ver=3.3.2:30
(anonymous) @ compiled.js?ver=3.3.2:35
value @ compiled.js?ver=3.3.2:35
onClick @ compiled.js?ver=3.3.2:35
r @ compiled.js?ver=3.3.2:16
a @ compiled.js?ver=3.3.2:16
u @ compiled.js?ver=3.3.2:16
d @ compiled.js?ver=3.3.2:6
g @ compiled.js?ver=3.3.2:6
r @ compiled.js?ver=3.3.2:30
processEventQueue @ compiled.js?ver=3.3.2:6
r @ compiled.js?ver=3.3.2:35
handleTopLevel @ compiled.js?ver=3.3.2:35
i @ compiled.js?ver=3.3.2:35
perform @ compiled.js?ver=3.3.2:6
batchedUpdates @ compiled.js?ver=3.3.2:35
i @ compiled.js?ver=3.3.2:6
dispatchEvent @ compiled.js?ver=3.3.2:35
VM722:1 Uncaught SyntaxError: Unexpected token C in JSON at position 1
at JSON.parse (<anonymous>)
at Object.callback (compiled.js?ver=3.3.2:6)
at compiled.js?ver=3.3.2:35
at d.callback (compiled.js?ver=3.3.2:35)
at d.<anonymous> (compiled.js?ver=3.3.2:35)
at d.r.emit (compiled.js?ver=3.3.2:35)
at XMLHttpRequest.n.onreadystatechange (compiled.js?ver=3.3.2:35)

Please suggest on the corrective action for this at the earliest.

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