You can convert into pkcs 12;
Importing a PKCS 12 (IIS) file
PKCS 12 is a specifically formatted archive file that is used for storing cryptographic objects in a single file. The PKCS 12 file has an extension of .PFX and is compatible with Windows IIS. To import a PKCS 12 file, perform the following steps:
Note: The BIG-IP system automatically converts PKCS 12 certificates to PEM format when the files are imported.
Impact of procedure: Performing the following procedures should not have a negative impact on your system.
Log in to the Configuration utility.
Navigate to System > File Management > SSL Certificates List.
Click Import.
From the Import Type list, select PKCS 12 (IIS).
In the Certificate Name section, type a name for the certificate.
In the Certificate Source section, click Choose File.
Click Import.
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