To fix Safaricom error 69 when sending sms message you need to dial #330*0000# and then restart your phone.
Solution 2: Go to message>settings and make sure that the sms service center number is +254722500029.
Solution 3: The error "Can't send message with Safaricom, error 69" can also mean that your phone's SMS app is not supporting sending messages (probably due to network issues). If restarting your phone has not resolved the problem, it is advisable to use the default sms message app for sending SMS messages. Go to apps on your phone and check if you have two SMS Messages app. If there are two, click on one of them and then go to Messaging App option, thereafter select the default sms app.
Solution 4: If all the solutions provided above do not work then the remaining one is to reset your phone.