somewhere along the line
US /ˈsʌmˌwɛr əˈlɔŋ ðə laɪn/
UK /ˈsʌmˌwɛr əˈlɔŋ ðə laɪn/

1.
どこかで, 途中で
at some unspecified point during a process or sequence of events
:
•
I must have made a mistake somewhere along the line.
どこかで間違いを犯したに違いない。
•
Things went wrong somewhere along the line, and we lost the deal.
どこかでうまくいかなくなり、取引を失った。