I suggest writing the article on a wordpress editor, and then copy-pasting the output in the visual editor below.
You may also have better luck copying the “text” version of the article and submitting that as a text submission.
Guest submissions are subject to moderation. They should not read as advertisements, and excessive linking is not allowed (a maximum of one useful backlink in a medium size post, and a maximum of two in a large one).
Referencing URLs from other articles published on S/Blog is permissible without a limit.
Articles should be relevant to tech, a current issue, or have some substance if unrelated.
For advertising (and not just contributing, ie. affiliate links and tracked campaigns to outside services), then please contact me beforehand and suggest a deal.