Azure. The system memory and CPU change cause slowdown app respond?

Hello, we had a problem at 24th of February between 12:35 and 12:50 (pm by utc). Our app starts to respond slowly and it led to failures, but our app didn’t overload

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Could the system memory and CPU change cause slowdown our app respond? If yes, then how can avoid this problem next time?
There is a screenshot of our app slowdown chart:
In this time we detect change in physical memory and CPU ,

Availability and Performance tools detected top 5 slow request execution. It is requests from our app service to external services. Could these requests the overall performance of the app service or app service plan?