@camoceltic @maiyannah
This is a server-side error. We encountered it a year or two ago. See my old post:

@mk Now I remember similar case! The problem was with wrong libraries at a server side, which didn't allow proper parsing of a correctly formatted multi-part messages:
@andstatus [Solved] I found a solution: It seems that # demands a PHP server which is running PHP with Apache module. My instance ran until now under PHP with FastCGI. I could switch in the Plesk panel. I …
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hiker
URL: http://status.vinilox.eu/notice/3059584
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andstatus@loadaverage.org
URL: https://loadaverage.org/notice/6781717