I would be surprised if the filename had any role in this problem. Please provide more detail: What is the content of the file, what is the output of storescp --debug? Is there a crash does the tool report an error and terminate? Which DCMTK version, which operating system?
W: DIMSE Warning: (art,art): sendMessage: unable to convert dataset from 'JPEG Baseline' transfer syntax to 'Little Endian Explicit'
E: Store Failed, file: C:\testing_1\1.2.276.0.26.1.1.1.2.2020.393.49676.3614986.180224000:
E: 0006:020e DIMSE Failed to send message
E: Store SCU Failed: 0006:020e DIMSE Failed to send message
W: DIMSE Warning: (art,art): sendMessage: unable to convert dataset from 'JPEG Baseline' transfer syntax to 'Little Endian Explicit'
E: Store Failed, file: C:\testing_1\1.2.276.0.26.1.1.1.2.2020.393.49676.3614986.180224000:
E: 0006:020e DIMSE Failed to send message
E: Store SCU Failed: 0006:020e DIMSE Failed to send message
My comment on this: option --propose-jpeg8 and --propose-lossless are mutually exclusive, the rightmost appearance wins, i.e. in this case --propose-lossless. Remove this --propose-lossless from the storescu call and it should work.
By the way, enabling the --debug log output is usually also quite helpful.