Subsystem sftp internal-sftp
</source>
Make sure, that <source lang="bash">Subsystem sftp internal-sftp</source> is the last line in the configuration file.
Execute:
FILE=/etc/ssh/sshd_config;
for ((x=0; x<101000; x+=1)); \
do \
printf "Match User *%03d\n" $x >> ${FILE}; \