First of all this long support line had only one (!!!) touch point since the starting point. If spot price holds above it, that would be the second higher low. So for example, this is one reason we can not call it a "trendline", as it is basically too long on both daily and weekly time frames and has too few "higher lows". So in my opinion this "support line"will become important only if it can force Price back up from now.
What is the chance? I think for short term it is quite good, as Price is not just testing this long term line, but also the lower band of the short term , and Slow has become oversold again. Meanwhile we all know how huge short positionning has been built since July in EURUSD . If Price can not close below this psychological level for 3 days in a row, than