Docker image fails to run

[kinga112]

Describe the bug
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Traceback (most recent call last):
File "/opt/kanmail/scripts/run_server.py", line 9, in
from kanmail.server.app import app, boot
File "/opt/kanmail/./kanmail/server/app.py", line 57, in
dsn=get_hidden_value("SENTRY_DSN"),
File "/opt/kanmail/./kanmail/settings/hidden.py", line 37, in get_hidden_value
data = get_hidden_data()
File "/opt/kanmail/./kanmail/settings/hidden.py", line 30, in get_hidden_data
return pickle.loads(b64decode(hidden_data))
EOFError: Ran out of input

hidden.json is empty so pickle fails.

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Additional context
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After a successful docker build, the image fails run.
Using MacOS and python 3.9.18

I tried with honcho as well, but I got other package errors.