Input Genotype file looks okay but still getting error

[Felix Lisso]

Dear concerned, 

 I have been running gemma, but I am getting the following error, although the input file is correctly formatted. 
 gemma -g mikk_small_hapVariants_updated_noheaders.txt.gz -p mikk_GN1038_pheno.txt -gk -o mikk_small_GN1038

GEMMA 0.98.3 (2020-11-28) by Xiang Zhou and team (C) 2012-2020
Reading Files ...
**** FAILED: Parsing input file 'mikk_small_hapVariants_updated_noheaders.txt.gz' failed in function ReadFile_geno in src/gemma_io.cpp at line 744

I have tried trouble shooting to know the exact problem, but  I have not succeeded. I would very much appreciate your help. 

Regards, 

Lisso