If you can't use this feature any more, then there must be a glitch, and I advise you
to email italki directly: firstname.lastname@example.org
That’s good of you as a community member to report such glitches to the wonderful people at italki support —
good advice from Mumtaz:
1. Switching to the classic site might take care of your issue. Simply replace "www" with "classic"
2. A few hours ago, another user suggested resolving the issue by logging in with Internet Explorer instead of Chrome.
You can find the answer here: http://support.italki.com/hc/en-us/articles/206353358-What-is-Premium-Membership-
Only premium members can send unlimited friend requests. If you are not a premium member you can send out only 2 per day.