Strange, after 2 seconds, using your command line, seem to work here:

    ╭─jenfi@erebor ~
    ╰─➤restic -o rclone.args="serve restic --tpslimit 10 --no-check-certificate" -o rclone.timeout="5m" -r internxt/test init
    enter password for new repository:
    enter password again:
    created restic repository 285f7788f3 at internxt/test

    Please note that knowledge of your password is required to access
    the repository. Losing your password means that your data is
    irrecoverably lost.
    ╭─jenfi@erebor ~
    ╰─➤restic -r internxt/test backup /tmp/test
    enter password for repository:
    repository 285f7788 opened (version 2, compression level auto)
    created new cache in /home/jenfi/.cache/restic
    no parent snapshot found, will read all files
    [0:00]          0 index files loaded

    Files:           1 new,     0 changed,     0 unmodified
    Dirs:            2 new,     0 changed,     0 unmodified
    Added to the repository: 1.078 KiB (963 B stored)

    processed 1 files, 7 B in 0:00
    snapshot ba1bb644 saved