hard drive – How to encrypt all partitions with BitLocker in Windows 10?

My storage is separated physically into two SSDs (let’s say SSD 1 and SSD 2)

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and logically into three partitions (C, D, E). I can encrypt the partitions C and D, that are stored on the SSD 1. But the partition E stored on SSD 2 is not displayed in the BitLocker management view:

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What might be the reason? How to fix that?