Error 38 when trying to send texts

[DavidEva_665840]

I am in Portugal and have tried to reply to a text from UK. I get error code 38. 

Am I doing something wrong and can I rectify this? 

[MSF]

@DavidEva_665840 Is the text coming from a standard type of UK number? If it is from a short code number then you cannot send a reply as Smarty does not yet support that system.