[TYPO3] installing extension, getting "Bad Gateway 502"

[Mike Klemin]

Hello,
I trying to install the Templavoila, and getting bad gateway error from the server. It happens either when I use on-line repository or file upload feature.
I got an advice to get Templavoila from my local test site and copy into typo3conf/ext/Templavoila
I did it, and allowed me to install the extension. But, after I installed the mininews extension (it installed fine, from online repositary) I was'nt able to use templavoila to templating mininews, the TAB "Other" was not active. 
I am bit tired with all of this, so may be I missed somethig... 
Let me know, if this is correct way to install extention the way I did it with Templavoila. If so, then I search the error in other things. 
thank you!

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Best Regards,
Mike Klemin
JSC "NevaLab"