No, there shouldn’t be a limit. I’ve not been able to reproduce this so far. Is there any other information you can give. For example:
- Are you sending private messages via the button shortcut or via Guild Control -> Members -> Name of member you were sending a PM to -> Private Message?
- Were the other players on near or faraway planets?
- Are you sending PMs to their main characters or their alts?
And anything else that may be of interest.
Faraway planets. And I only knew of one way to send pms lol. Thru pressing the touch pad and going to private message. I believe that was Aeneas main and that was an alt for Ajax
I will get back to you on that! 
Will be offline for a few hours, will talk after!
And yes, the messaging is still rather wonky! I’ve noticed several times I see that I have a PM, select the user name with a number behind it, nothing there!
Using channel ALL seems to be the most reliable for checking stuff since they usually appear there tho. But am sure I’ve missed many a PM because of this, sigh 
Also, why are ‘whispers’ still not able to send the msg to the currently playing alt of the same person like with PM’s?
And while we’re at it what’s wrong with the servers lately that 6 times out of 10 in sanctum I get SERVER OFFLINE, try later or select other destination. Then 30 seconds later it retries to open and it works. First message was a lie then! 
Also, seems like all the servers might need a reset, some of them are really, really laggy again (especially the AU ones, but the USW ones too, well, for me at least from EU).
Just tried it right now again sending a message to Kagenokami. He’s on Xa Fant and I’m in Maluriakrib. Got the same message. Going to submit my game log
This is a bug and will be fixed in a hotfix ASAP.