Migrated site does not use https for included resources anymore

We copied the database and files for a production site to a staging server. We used search and replace to update all the internal links to the new domain. The staging version works, but some resources are being pulled using http rather than https. This was not a problem on the source server. We noticed this because a YouTube embedded video is not being displayed on the home page, but upon further investigation it seems fonts and other resources are also being accessed with http instead of https.

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