I think you are setting some weird - non-latin1 encodable - cookie or general header values for fanbox in your two (why?) config files.

What do your fanbox cookie settings look like? (censor any sensitive values)

as for unknown reason any installations attempted via py -3 install commands are not recognized as existing (typing in gallery-dl in command prompt after the installation and without the standalone executable results in the command not being recognized

You need to either update PATH or use py -m gallery_dl ...: See #6624

Now it says something about cloudflare challenge or something (for both with and without the py -m thing) instead of problem with encodable thingy, and I literally just came back from work so I did not change anything until this time.

C:\Users\USERNAME>py -m gallery_dl https://www.fanbox.cc/@memechan --verbose
[gallery-dl][debug] Version 1.28.1
[gallery-dl][debug] Python 3.12.8 - Windows-10-10.0.19045-SP0
[gallery-dl][debug] requests 2.32.3 - urllib3 2.2.3
[gallery-dl][debug] Configuration Files ['%USERPROFILE%\gallery-dl.conf']
[gallery-dl][debug] Starting DownloadJob for 'https://www.fanbox.cc/@memechan'
[fanbox][debug] Using FanboxCreatorExtractor for 'https://www.fanbox.cc/@memechan'
[urllib3.connectionpool][debug] Starting new HTTPS connection (1): api.fanbox.cc:443
[urllib3.connectionpool][debug] https://api.fanbox.cc:443 "GET /post.paginateCreator?creatorId=memechan HTTP/11" 403 None
[fanbox][warning] Cloudflare challenge
[fanbox][error] HttpError: '403 Forbidden' for 'https://api.fanbox.cc/post.paginateCreator?creatorId=memechan'
[fanbox][debug]
Traceback (most recent call last):
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python312\Lib\site-packages\gallery_dl\job.py", line 151, in run
for msg in extractor:
^^^^^^^^^
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python312\Lib\site-packages\gallery_dl\extractor\fanbox.py", line 59, in items
for content_body, post in self.posts():
^^^^^^^^^^^^
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python312\Lib\site-packages\gallery_dl\extractor\fanbox.py", line 340, in _pagination_creator
urls = self.request(url, headers=self.headers).json()["body"]
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\USERNAME\AppData\Local\Programs\Python\Python312\Lib\site-packages\gallery_dl\extractor\common.py", line 244, in request
raise exception.HttpError(msg, response)
gallery_dl.exception.HttpError: '403 Forbidden' for 'https://api.fanbox.cc/post.paginateCreator?creatorId=memechan'

I was originally using --cookies pathtotheexportedcookies.txt command, but I manually added them in the config file just now too (my config file was originally missing cf_clearance and __cf_bm, if that is of any relevance. I do not remember when the config file first appeared or how I got it, but I am absolutely sure I did not make it myself).

I don't know anything about two config files, I only see one in the same folder as the gallery-dl.exe.

"fanbox": {
"metadata": true,
"directory": ["{user[name]}", "{date:%y.%m.%d} {title}"],
"filename": "{filename}.{extension}",
"postprocessors": [
{
"name": "metadata",
"event": "post",
"filename": "{date:%y.%m.%d} {title}.txt",
"mode": "custom",
"format": "{content}"
}
],
"cookies": {
"FANBOXSESSID": "numbers_numbersandletters",
"cf_clearance": "longlineofnumberslettersanddashes",
"__cf_bm": "shorterlineofnumberslettersanddashes"
}
}

I reinstalled python 3.12.8, making sure to check the box that says add to PATH before finishing installation. Now gallery-dl command is accepted even after I delete the standalone executable, but the cloudflare challenge thing still persists. I just tested it with another website (subscribestar) and it worked fine.

Exported cookies .txt file content:

Netscape HTTP Cookie File

http://curl.haxx.se/rfc/cookie_spec.html

This is a generated file! Do not edit.

.fanbox.cc TRUE / TRUE 1738049376 p_ab_id 0
.fanbox.cc TRUE / TRUE 1738049376 p_ab_id_2 5
.fanbox.cc TRUE / TRUE 1738049376 p_ab_d_id 309357378
.fanbox.cc TRUE / TRUE 1736380166 FANBOXSESSID numbers_numbersandletters
.fanbox.cc TRUE / TRUE 1768348166 privacy_policy_agreement 0
.fanbox.cc TRUE / TRUE 1768348166 privacy_policy_notification 0
.fanbox.cc TRUE / TRUE 1733789966 __cf_bm shorterlineofnumberslettersanddashes
.fanbox.cc TRUE / TRUE 1765324167 cf_clearance longlineofnumberslettersanddashes

.fanbox.cc TRUE / TRUE 1765324167 cf_clearance longlineofnumberslettersanddashes

Good. You need this cf_clearance cookie (you might need to update it again) together with the user-agent header of your web browser in orderf to bypass "Cloudflare challenge" pages.

See #5791