1. The CRL file did not exist.
2. The CRL file had been imported.
3. The number of imported CRL files exceeded the upper limit.
1. If the CRL file did not exist, import the correct CRL file.
2. If the CRL file had been imported, no action is required.
3. If the number of imported CRL files exceeded the upper limit, delete unnecessary CRL files to provide sufficient space for the CRL files to be imported.