How to fix discrepancies in conversions?

Question

Google Analytics

Hello!
Such a problem
Through Google Tag Manager, conversions are tracked, which are subsequently sent to Google Analytics, and from Analytics they are sent to Google Edwards (export).
The problem is that for some reason I have discrepancies in Google Adwords with Analytics.
For example, in analytics I have 5 conversions for the first interaction in an advertising company, and in Google Advances 0 in the same advertising company (the period is set both there and there the same).
This problem is observed in almost every advertising company. Or discrepancies in 1-2 conversions, well, or a significantly larger discrepancy.
With what it can be connected?

Answer 1

Is the attribution model in Adwords the same - on the first click?