HTML Email DON'T work for me in v1.3.8a/v1.3.8 with various addons

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hello all!!!

have problem: Zen Cart don't sent ANY email in HTML format. i read threads in forum and testing examples, but it not work. my config:

E-Mail Options:
E-Mail Transport Method --- sendmail
Use MIME HTML When Sending Emails --- true
Email Admin Format? --- HTML

Customer Details:
Customer Default Email Preference --- 1

server on Linux. email sents fine in TXT format.

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Forgive for anxiety )

I have found - this problem with mail not in a pure Zen Cart v1.3.8a. I think a problem in the third part template or any mods, an example in Url SEO or Google Sitemap/Base. The theme Cherry Zen is used. Have any ideas?