@TPint It seems like this is because of your mobile service provider or the landline (PSTN) provider - contact them to be sure.

@summoned In your case, perhaps a different approach like the one described here, would be a possible workaround.

@summoned Probably the culprit here is with the VPS settings. In general, if you want to expose an FTP server behind your AX20 to the Internet, here's a guide on that.

@Daarnu Apparently (from an old thread) there's no solution existing but you can turn off Malicious content filtering as a workaround.

@gtcislandgal Best approach would be to reset the RE650 to factory defaults and re-configure it from scratch. To reset the RE650 press its reset button for about 10 seconds, To configure use this...

@Eliashatzis This guide should be able to help you with that.