Why do I get "IMS Service Has Stopped" Message after update
Settings &rarr; Applications &rarr; Default Applications and I set the Messages from Messages to Client, this stopped the pop ups.

Further to this having set Messages to Client I then found out the offending app was myMail, which I uninstalled and was able to set Messages back from Client to Messages

Hope it helps.

The Client is the default message service of Android I believe and the Messages is Samsung Galaxy S5 Neo's own software, I could be wrong, I'm not an expert, I just know how I fixed mine. So following the above, this Client app should be available. Beyond that I'm sorry, I cannot help.