At risk of invoking memories of playground rejection by wading in to the sensitive topic of whose a friend of who, I thought this was an interesting story worth telling.
Now this is interesting as although I haven't met Leo personally we do exchange the odd email and are "friends" on most of the other social media sites. It is totally possible that Leo wants to limit the number of people he friends as he re-enters Facebook but this block appears to have pre-empted any message to Leo. There may be some setting in Facebook that lets him pre-set who gets to send friend requests that I don't know of.
Wondering why this error message might have been triggered I looked at the suggested help file I got the following advice:
If you have been prevented you from adding friends on Facebook, it is likely because many recent friend requests sent from your account have gone unanswered. This may be because you’ve asked strangers to be friends or because you’ve engaged in other behavior that Facebook users have reported as unwelcome. When you are allowed to use this feature again, only send friend requests to people that you already know to avoid having additional limits placed on your account.
This seems hard to understand as I can't remember the last time I tried to add a friend in Facebook as it is so long ago and I only ever do it to people I do know in some way I can't imagine too many people blocking me. In fact I thought of seeing if the block applied to others apart from Leo but could't bring myself to do it as I have already friended everyone I can think of in Facebook and didn't want to be seen to adding someone I don't know!
Clearly Facebook knows something I don't!