ERROR: LoadError: KeyError: key "1" not found

[MitoSri]

Hi I am using a VCF file generated from mutserve2. This is the error I get
"ERROR: LoadError: KeyError: key "1" not found"
Below is the header of Vcf file
##fileformat=VCFv4.2
##FILTER=<ID=PASS,Description="Variants passed mtDNA-Server">
##FORMAT=<ID=AF,Number=1,Type=String,Description="Inferred Allele Frequency of top (non-reference) allele">
##FORMAT=<ID=DP,Number=1,Type=Integer,Description="Read Depth">
##FORMAT=<ID=GT,Number=1,Type=String,Description="Genotype">
##Mutserve=v2.0.0-rc13
##contig=<ID=MT,length=16299>
#CHROM

What is key "1" in the vcf file that is not found ? I am using only one contig- The mitochondiral