After googling about a bit, I hit on a likely thread.

I suspect that the actual message is something like the following. The piece that you specifically mention is in bold.

お掛【か】けになった電話【でんわ】は電波【でんぱ】の届【とど】かない場所【ばしょ】か​電源【でんげん】が入【はい】っていないため​かかりません。

Breaking down the translation of the bolded portion:

電源【でんげん】　　が　入【はい】っていない　ため
power [SUBJ] in 　 is not 　because →
because the power is not on

Please comment if the above does not fully address your question.

After googling about a bit, I hit on a likely thread.

I suspect that the actual message is something like the following. The piece that you specifically mention is in bold.

お掛【か】けになった電話【でんわ】は電波【でんぱ】の届【とど】かない場所【ばしょ】にあるか​電源【でんげん】が入【はい】っていないため​かかりません。

Breaking down the translation of the bolded portion:

電源【でんげん】　　が　入【はい】っていない　ため
power [SUBJ] in 　 is not 　because →
because the power is not on

Please comment if the above does not fully address your question.