There are times Google AdWords will not verify third party tracking numbers because bots cannot see the number when they crawl the site. To bypass this, you need to link your AdWords account to the Search Console inside of AdWords. By linking AdWords and Search Console, there will be no need for the bots to crawl your site.
If AdWords and the Search Console is not linked, Google will need to verify the ownership of the phone number by going to your website and comparing numbers. If your call extension numbers do not match (which is the case since you're using Call Sumo's Ad Extension tracking numbers), they will not approve the ad.
Fo a flawless and more manageable reporting, we recommend having separate numbers for Google AdWords, Ad Extension, and call-only ads.
For more information on Call Tracking for Ad Extensions, please refer to this article.