This happens for xdebug module.It's crossed nesting level.Just increase it as recusive.For more follow here http://www.kingpabel.com/xdebug-recursion-limit/

@creativeorange very well said, I see everyone is giving the hack but not the perfect solution or the cause of the problem.

For those of us who don't got no advanced-level apps going on like some of these guys;

In my case, I had to revisit my blade templates - I had to too many instances of @extends('layouts.app'), @yields & @includes going on - cleaning up these got me going again!

I had this same issue when sending a queued email. I increased the max nesting level to 10K (just to see what would happen) and the error continued. Looking at the log file, I noticed there were hundreds of calls to Illuminate\Database\Eloquent\Model::getQueueableRelations() (line 1422 on L5.7 to be precise). Removing the Illuminate\Queue\SerializesModels trait from the mailable class solved the issue (not needed for me anyway).

@PLENTY - I wanna buy you a beer dude. Spent the last few days tearing my hair out with all these dumb workarounds and all I needed to do was consolidate a few blade files...

I'm definitely noting this one down in my list of odd issues. I can't recall reading anywhere that too many blade includes can break the site. Maybe a line in the docs would save a few people some headache.