messagingtoolkit

hello, we're having a problem that seems to occur randomly (but alot these days)
mainly we have an automated application that loads a list of messages and recipients once per day, then sends the messages using a Huawei USB Modem

i have a log file but i don't think it'd be appropriate to upload it to a public forum

one record

2014.01.08-11.19.15: CMS ERROR: 500     Unknown error
2014.01.08-11.19.15: Sending message: Unsupported feature: SendSmsFeature: Send SMS (CMS ERROR: 500     Unknown error)
2014.01.08-11.19.15: Sending: AT+CMGL=4
2014.01.08-11.19.15: Trace:    at MessagingToolkit.Core.Mobile.BaseMobileGateway`1.SendMessage(Sms message)
   at MessagingToolkit.Core.Mobile.BaseMobileGateway`1.Send(IMessage message)
2014.01.08-11.19.16: Response: <cr><lf>+CMGL: 0,1,,47<cr><lf>0791198902024564040C91199903764110000031407160000522205436688E2EEBC36490181D4EABC36E900C346683DA65505D7E76B3F3<cr><lf>+CMGL: 1,1,,43<cr><lf>0791198902024564040C911999037641100000314071607395221BD4B43B0CA2B341627438AD0EBB41B2311BD42E83EAF2331D<cr><lf>+CMGL: 2,1,,130<cr><lf>0791190903500520040BD0C4E7F0D97C020000314071113032227EC87408947DD7E5A02054DA8ACD40E2349B0D7A9B41D239E8269B81CC6F390897BBD96032DA6C36FB81D0E139485C2EBB41E7B2BB2C0FD3CB6417081ACEB7CB6E3A283D0791EB65D0DB0D82D15ACD60B6159BB940C6B71C244EB3D92072991E4EB3E720723ACC06A962B9988A367201<cr><lf>+CMGL: 3,1,,141<cr><lf>07911909235205200410D0D4608BF81C3E9B4F00003140029032622289C87408947DD7E5A02054DA8ACD40E2349B0D7A9B41D2B9EB269BB9623490F92D07E172371B4C469BCD662074780E1297CB6ED0BCECA683E86F50FE5D7781B2EFBA1C34AECBE565371DF4AED3E7F4B09B9C769F416F33483A77DD6433507A0E22D7CBA0B71B04A3B560B5566C066A51C3F43088F81EBFDB6F<cr><lf>+CMGL: 4,1,,158<cr><lf>07911909235205200410D0D4608BF81C3E9B4F0000314012904232229CD9775D0E12A7D96CD0DB0C0A42A5ADD80C647ECB41D4303D0C0A8EC7EFBA9B0E72BF41B95BCE96C3C16A38103A3C0789CB6537889C9EC3C3F431BA4C7641D97350BBECA6A7DF6E903BDC2EB34070B41BE47EB340F2F2B89CB697C92072985E069940F2323B4C4FBFDDA0B71B047D1241F2F2B89C86D341F437685E96DBCBA0FCBB0E1297E9F4B2DC05<cr><lf>+CMGL: 5,1,,161<cr><lf>07911909235005300410D054628BF81EBFDB6F000011214211646522A04669B1084A528BCDA4B6480409934C26C8FC9683F2EFBA1C047DCFE9F0701EE4AEB7C565B94B5A3EA7E7F4B21C647ECB41456192C964CDE96F38081A8416A520719ACD0685DD6410BACC8683924E6232083ABF416779B9EC760DC36C3628268B81E86F72380FA2BF41F2F2393DA797E520F35B0EA2A3D37390515A2C829E466351EAA206A94110F1397C369F<cr><lf>+CMGL: 6,1,,160<cr><lf>07911929055205800410D05462CB76B3D562300000211050316103229ECCF01A3D07BDCD2078F90D679741617919340FDBD3EE33E8ED06D1D1E5B41CD47E8BD3EC32485E1EA3C3F273790E12E741F3B29B9C769F4155373BDD4ED3CB6490515A2C82A6CD29C82C7FB741F7FBDD65ACB3D94FF7B43D778DDF6D50D23DA787DD7410B9CC4EDBCBF23C0B5477B3D3ED34BD4C069DE5EF3A7C0E3281DA6F79D90552BED36E90FB7D0F01<cr><lf>+CMGL: 7,1,,22<cr><lf>0791198912000050040C9119891237941600002110509190732203BA1408<cr><lf>+CMGL: 8,1,,32<cr><lf>0791198944914814240C911989448145280000211080325305220EC47258EE0235D3EEF03DCC0E03<cr><lf>+CMGL: 9,1,,156<cr><lf>07911909925605902409D93599AC56030000314042705500229DC87408947DD741E8B0BD0C9A819AE9F9BC4C068DC36CF6DC457D83CE653A885CA687D3EC39E86D0699D3F2391D3403B5D3F379990C1A87D9EC396BDA9C828E452A88FE06D564B25A0D049096632EE35B0E0AB3D9A0667A3E2F9341E3309B0D2297E9E1347BCE9AB7E7A0293528A582E86F504D26A3D14026D0BC2E9E8FE56971190490CE63B557938E06<cr><lf>+CMGL: 10,1,,42<cr><lf>0791198901508192040C911989015017260000314052807061221A54747A0E4ACF41EE371D640FBBC9EEF01CE4AEB7C56539<cr><lf>+CMGL: 11,1,,159<cr><lf>0791198944914814400C91198944814528000021109000212022A005000316020188E5B0DC056AA6DDE17B981D768192A0701B54C6D3E5E576999D07CDDF72791E647ECB41EE371D242FC3D9F9B4FB0CA2BF41F9771D540ECBD9E9B21C149E83D2A07B780E7AD7E9A0B719947693D36150D84D06B1C3F4B21C642FCBF3A0797ABC0685D9EDF79C0E32BFE5A030A8FD76D3D12037081D669B41737A9ACD06A541E136C85E96E741<cr><lf>+CMGL: 12,1,,143<cr><lf>0791198944914814640C911989448145280000211090002140228D050003160202EEE5F01AC44A83EE69361B34AFCBCBEC3C68FC6E9741F437A82E07CDD16F38E88E2EBB4169D0F8DD2E83E86F50BBDE1687D3203A3AEC5ECF416FF7B80C0A9FC369370814769341F4F0BA0C1A87E56517E89A9EA341755098CD06D1C56590B83CA7BB5C4DF91C7444BFEBF37418040DD3D161B7CBE502<cr><lf>+CMGL: 13,1,,26<cr><lf>0791198901508192040C91198901319727000021101101048522085474D8BDCEBFEB<cr><lf>+CMGL: 14,1,,28<cr><lf>0791198912000050040C911989129756340000211021711335220A5474D8BD06E5DF7517<cr><lf>+CMGL: 15,1,,159<cr><lf>0791197920005055440C91195949898795000021104190929422A0050003030201402057ABC50A894422914824128944A29002F46AFD42201035C96C1DAB4C1008145280442D40EB2412894E2211E004102914D434FB5C6783D66190B9CE6683A8F2FA780D12A3CBEA30081D4EB314311A881E96A7D7207A700D0A8741EA70BE7C0E8714EA343DEC0E83C6E830BA0C629741ECB23B0C7ACB41D3B078FD0619DFF2FB9B0C5A87E5<cr><lf>+CMGL: 16,1,,41<cr><lf>0791197920005055440C9119594989879500002110419092152219050003030202DC6110090000B05C1B543BEC7EAB3729<cr><lf>+CMGL: 17,1,,98<cr><lf>07911909235205200410D0D4608BF81C3E9B4F00003140728093552258C87408947DD7E5A02054DA8ACD40E2349B0D32BFE5205CEE6683C968B3D90C840ECF41E272D90D2297D9697B595E2683E86F50FE5D07BDDD20D9AC15844A5BB119A8450DD3C320E27BFC6EBF5D<cr><lf>+CMGL: 18,1,,159<cr><lf>07911909235205200410D05462CB1683C168390000315010814120229D5774D90DAA83E66938284D6781E8E8B47B0D7A9B41F5B90B24ACE74161D0F86D3697CBA0B09B0C3A97E9A0B7BB0C32CBCBE51028E82683EEE83CC8FDA6B340EC72989C769F41E3B7D95C2E83C6E870DA3D07D5E76510354C0F8388CFE1B3F904B9CBF4FB5BBE7681A6CD29E8046556A72710FD0DAAD96C36180C0632BFE520B3BC5C06BDCDE6B27CEE02<cr><lf>+CMGL: 19,1,,41<cr><lf>0791198902004544040C91198902041920000031501091718322195474D8BD9E83CC6F3928FFAECB41EDF27C1E3E974121<cr><lf>+CMGL: 20,1,,159<cr><lf>07911909235205200410D0D460CB1683C168390000315060219444229D5774D90DAA83E66938284D6781E8E8B47B0D7A9B41F5B90B24ACE74161D0F86D3697CBA0B09B0C3A97E9A0B7BB0C32CBCBE51028E82683EEE83CC8FDA6B340EC72989C769F41E3B7D95C2E83C6E870DA3D07D5E76510354C0F8388CFE1B3F904B9CBF4FB5BBE7681A6CD29E8046556A72710FD0DAAD96C36180C0632BFE520B3BC5C06BDCDE6B27CEE02<cr><lf>+CMGL: 21,1,,136<cr><lf>07911929645205900410D0D4608BF81C3E9B4F0000217060112383228354747A0E4ACF4161103C9C6F97DD7490BCDC4EBBC96539C8FC9683F2EFBA1CF4B697E5E47A19244EB3D92072985E26839455672B2603BDCD20E9DC25A3D5402E10945D0ECFCB2078380F4AB7DB65723A4C2FB3F320FA1B347EBBE96977BD0C2ABBD5EF7CDA7D06BDEB72D0BC2CB7A7C7E5B90B<cr><lf>+CMGL: 22,1,,156<cr><lf>07911929055305800410D05462CB2683C96C350000217060511332229A41B73ACC4E839AF535BA2C5797CB206439CCA6A341D4373DCCD635DFEEF9FBED0635C3737A1AF4369BCBF21088F99E9741D772FA8CA683A8E8F41CD47CBBE7EFB7DB752CD341E4F47CFCAEBBE9A072BC1E6683E86F50FE5D9783EEE1F49C0E9AA7F5659735CC4E9341F4349B0DC2819475769E356FCF415366B209A2BF4139990C06CBC9643018<cr><lf>+CMGL: 23,1,,150<cr><lf>0791194943909979040C9119491364685100002170705181402295D967550A3A4E9B20E713840C4E41D7A7131490D5602C180C064A3A41546411347C0E83A0E1931904319F4EE2D3097A32B34D6872380541A5CFE6D305323EA5A02133986C4E41D3A2930872069B4516A8F91426994590F3C90A1289D2E274CA2A36834926284904519FA0F17B1C1EBFD9E1FA5A068BC9E0F237809DB6975DE3B7ABBE06<cr><lf>+CMGL: 24,1,,150<cr><lf>07911909235305200410D05462AB96A3D972390000217080210473229331DB51089A42B320649A4C2EBB41C370BB2C0F83D26E10B4E804C96439D8AB059A42B320649A4C2EBB41C370BB2C0F83D26ED0B298050D91C1A41314CBE572AF16680ACD829A6F719A5D06C972B9DCAB059A42B32061F50892E572B9570B647CCB4161771E34856641C4B23D3D2ECF5DA0797B0E0A3A834E2288FE06D56CB01B0C<cr><lf><cr><lf>OK<cr><lf>
2014.01.08-11.19.16: Sending message to +91XXXXXXXXXX
2014.01.08-11.19.16: Content: REMOVED FOR PRIVACY
2014.01.08-11.19.16: Sending: AT+CMGS=147
2014.01.08-11.19.17: Response: <cr><lf>> 
2014.01.08-11.19.17: Sending: REMOVED FOR PRIVACY