Im not sure if something is wronf, here is my console output.

o.reload "RustTranslationAPI"
Unloaded plugin RustTranslationAPI v1.1.0 by Arainrr
[RustTranslationAPI] Start downloading the translation files.
Loaded plugin RustTranslationAPI v1.1.0 by Arainrr
ArgumentException: Path is empty 

The last line

although after another reload, the Path error has gone. Maybe it needed time to do something?..

o.reload "RustTranslationAPI"
Unloaded plugin RustTranslationAPI v1.1.0 by Arainrr
[RustTranslationAPI] Start downloading the translation files.
Loaded plugin RustTranslationAPI v1.1.0 by Arainrr

Merged post

Although I did just now get this

[RustTranslationAPI] The 'af' language file does not exist.
[RustTranslationAPI] The 'ar' language file does not exist.
[RustTranslationAPI] The 'ca' language file does not exist.
[RustTranslationAPI] The 'cs' language file does not exist.
[RustTranslationAPI] The 'da' language file does not exist.
[RustTranslationAPI] The 'de' language file does not exist.
[RustTranslationAPI] The 'el' language file does not exist.
[RustTranslationAPI] The 'en-PT' language file does not exist.
[RustTranslationAPI] The 'es-ES' language file does not exist.
[RustTranslationAPI] The 'fi' language file does not exist.
[RustTranslationAPI] The 'fr' language file does not exist.
[RustTranslationAPI] The 'he' language file does not exist.
[RustTranslationAPI] The 'hu' language file does not exist.
[RustTranslationAPI] The 'it' language file does not exist.
[RustTranslationAPI] The 'ja' language file does not exist.
[RustTranslationAPI] The 'ko' language file does not exist.
[RustTranslationAPI] The 'nl' language file does not exist.
[RustTranslationAPI] The 'no' language file does not exist.
[RustTranslationAPI] The 'pl' language file does not exist.
[RustTranslationAPI] The 'pt-BR' language file does not exist.
[RustTranslationAPI] The 'pt-PT' language file does not exist.
[RustTranslationAPI] The 'ro' language file does not exist.
[RustTranslationAPI] The 'ru' language file does not exist.
[RustTranslationAPI] The 'sr' language file does not exist.
[RustTranslationAPI] The 'sv-SE' language file does not exist.
[RustTranslationAPI] The 'tr' language file does not exist.
[RustTranslationAPI] The 'uk' language file does not exist.
[RustTranslationAPI] The 'vi' language file does not exist.
[RustTranslationAPI] The 'zh-CN' language file does not exist.
[RustTranslationAPI] The 'zh-TW' language file does not exist.
[RustTranslationAPI] Failed to download translations files. Code: 0. Error: Request timeout

😳your server doesn't seem to be able to download the translation files...

very odd
I'll reload it again

Merged post

o.reload "RustTranslationAPI"
Unloaded plugin RustTranslationAPI v1.1.0 by Arainrr
[RustTranslationAPI] Start downloading the translation files.
Loaded plugin RustTranslationAPI v1.1.0 by Arainrr
ArgumentException: Path is empty

ArgumentException: Path is empty
at System.IO.Directory.CreateDirectory (System.String path) [0x00016] in <fb001e01371b4adca20013e0ac763896>:0
at Ionic.Zip.ZipEntry.InternalExtract (System.String baseDir, System.IO.Stream outstream, System.String password) [0x00298] in <510a9a0a2eb84c1caa23d4acd845fea7>:0
at Ionic.Zip.ZipEntry.Extract (System.String baseDirectory, Ionic.Zip.ExtractExistingFileAction extractExistingFile) [0x00007] in <510a9a0a2eb84c1caa23d4acd845fea7>:0
at Oxide.Plugins.RustTranslationAPI+TranslationsDownloader+<DownloadTranslations>c__Iterator0.MoveNext () [0x00257] in <797667c6c6414170909f2e3e3fc3ae61>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) [0x00026] in <0b31faaf1c50461d95c83ac166a20393>:0

Fixed in latest vestion