Server inaccessible when playing certain files

Hi, I've been using Serviio for a long time and I'm sure it's the best media server around.
Form version 1.2.1, I started to let Serviio paste subtitles into my mkv files without trouble. But certain times, when I play a mkv file with external subtitles, my Bravia TV gives me an error (Server inaccessible). If I try to play the file from my phone or from my xBox, it just doesn't play.
If I disable merging subtitles, the file plays fine.
But it happens only on certain files. There is a lot of MKV with the same size/quality I can play just fine merging subtitles.
Any idea, a pattern of why certain files play, and other doesn't?
Thanks

This is MediaInfo data of a file than doesn't work when merging subtitles:

General
Unique ID : 251345352473572974670154771773832739960 (0xBD175AA46806BE2D8C65C7DF3906BC78)
Complete name : D:\Videos\Series\Les Revenants\Les Revenants.S01E02.Simon.HDTV.720p.mkv
Format : Matroska
Format version : Version 4 / Version 2
File size : 1,16GIB
Duration : 50min.
Overall bit rate : 3 280Kbps
Encoded date : UTC 2013-02-01 04:54:23
Writing application : mkvmerge v6.0.0 ('Coming Up For Air') built on Jan 20 2013 09:52:00
Writing library : libebml v1.3.0 + libmatroska v1.4.0

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Si
Format settings, ReFrames : 5marcos
Codec ID : V_MPEG4/ISO/AVC
Duration : 50min.
Bit rate : 2 767Kbps
Width : 1 280pixeles
Height : 720pixeles
Display aspect ratio : 16:9
Frame rate mode : Constante
Frame rate : 25,000fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8bits
Scan type : Progresivo
Bits/(Pixel*Frame) : 0.120
Stream size : 1 006MB (84%)
Title : French
Writing library : x264 core 129 r2230 1cffe9f
Encoding settings : cabac=1 / ref=5 / deblock=1:0:0 / analyse=0x3:0x113 / me=umh / subme=8 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=2 / b_bias=0 / direct=3 / weightb=1 / open_gop=0 / weightp=2 / keyint=250 / keyint_min=25 / scenecut=40 / intra_refresh=0 / rc_lookahead=50 / rc=crf / mbtree=1 / crf=18.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00
Language : Francés
Default : Si
Forced : No

Audio
ID : 2
Format : AC-3
Format/Info : Audio Coding 3
Mode extension : CM (complete main)
Format settings, Endianness : Big
Codec ID : A_AC3
Duration : 50min.
Bit rate mode : Constante
Bit rate : 448Kbps
Channel(s) : 6canales
Channel positions : Front: L C R, Side: L R, LFE
Sampling rate : 48,0KHz
Bit depth : 16bits
Stream size : 163MB (14%)
Title : French
Language : Francés
Default : Si
Forced : No

Texto
ID : 3
Format : UTF-8
Codec ID : S_TEXT/UTF8
Codec ID/Info : UTF-8 Plain Text
Title : Español
Language : Español
Default : Si
Forced : No

...And this is Serviio Log File. I've read it has trouble reading subtitles, please check where it says "This is a possible error" and the path to the SRT is wrong (subtitles=filename="D\\:/Videos/Series/Les Revenants/Les Revenants.S01E02.Simon.HDTV.720p.srt")
Thanks in advance

I've found out the problem was in the srt file, it was kinda corrupt, although it plays fine locally.
I've downloaded a Subtitle Editor,fixed common errors (mainly empty lines) and now my MKV plays fine.
Thanks to everyone that read the post, and I hope this solution helps others with the same problem.