Augustus error of invalid character in FASTA file

[anushakankaria18]

I trained augustus and tried running on my masked FASTA file for the gene prediction but it is showing me this error of invalid nucleotide encountered.

s2769179@egadmin-HP-EliteDesk-800-G3-TWR:$ source /conda/bin/activate
(base) s2769179@egadmin-HP-EliteDesk-800-G3-TWR:$ conda activate augustus
(augustus) s2769179@egadmin-HP-EliteDesk-800-G3-TWR:$ augustus --species=glycinemax "/home/s2769179/ncbi-cxx-toolkit-public-release-29.0.0/src/app/winmasker/MC50_masked.fasta" > MC50_output.gff

augustus: ERROR
Invalid nucleotide '' encountered.

(augustus) s2769179@egadmin-HP-EliteDesk-800-G3-TWR:~$ grep "" /home/s2769179/ncbi-cxx-toolkit-public-release-29.0.0/src/app/winmasker/MC50_masked.fasta

^C
(augustus) s2769179@egadmin-HP-EliteDesk-800-G3-TWR:~$ grep "\" /home/s2769179/ncbi-cxx-toolkit-public-release-29.0.0/src/app/winmasker/MC50_masked.fasta
grep: Trailing backslash

If anyone knows how this error could be troubleshooted, kindly let me know.