I understand that you need help with the issue of page reach. For this information, I would like to present the following:
There are many factors that affect reach, including how people are engaging with your Page's content, how people have engaged with similar types of content in the past, the quality of the content and other factors such as time of day and whether people are on Facebook on their mobile phone or computer. It's normal for reach to change based on these factors.
There are two main reasons.
The first reason involves a simple fact: More and more content is being created and shared every day. You’ve probably felt this change yourself. Just a few years ago, sharing important moments and experiences, articles you’ve read, and photos and videos of your loved ones was a relatively labor-intensive process. Today, thanks to devices like smartphones, many people can share this content with just a few swipes of the finger or taps of a button.
There is now far more content being made than there is time to absorb it. On average, there are 1,500 stories that could appear in a person’s News Feed each time they log onto Facebook. For people with lots of friends and Page likes, as many as 15,000 potential stories could appear any time they log on.
Please do not worry currently most of the Pages are going through the updates because of this some Page may be facing this type of issue about the reach.
You need to check your external links because it could be possible people are giving negative reviews regarding the external links.
Hope the information I provide has been helpful to you, hope you will have an adjustment plan in your business and advertising plan to minimize the impact of the problem on your business.
If you have any other requests or questions, you can initiate a new support session at http://facebook.com/business/help to get help as soon as possible. You will soon receive an automated survey about the support service we have provided. I would like to summarize the support session on the issue: page reach and I have also shared with you the information related to this issue. I will close the support session after this email.