Site loads with unwanted characters for guest users when "W3 Total Cache" is defined in wp-config.php

Question

When a user is logged in, site loads without any problem but if a guest user visit the site, it shows some characters same as this:

O-y²ee·¹”sÆlæ#u«lB,G«gƯæÚå¿—TYûKä!E"¢ØÀÕìS<ðEùànú0"¸µq8ÜW1K™1ìµPóåÄ8D²ŠmmâP¦lËJzñC¥R#Íñ&À…¦Z0D"†˜y‘„¡«vb›‡l1yZ>ÑʬnìÛÉ«âÅV7±³ W+Š

and nothing else shows

Im using Q2A with wordpress integrated

Q2A version: 1.6.3

Edit:

I reuploaded all Q2A files and nothing happened.

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I found that Q2A get in trouble when I define "W3 Total Cache" in wp-config.php

Answer 1

As I thought problem was W3 Total Cache plugin.

disabling "Page Cache" in W3 Total Cache can solve this problem temporary.

I seeking for a better solution if possible.