Yep, same issue here, the old "bug" that others were hit with has finally happened to me too. Just 4 searches count, mobile or pc, then it's locked down for who knows how long. And actually one time it only gave me 3 searches before locking it out. NOT going to do the idiotic suggestions, they're a pointless boondoggle, this is just MS being MS and either they "updated" something (and never told us) or they're just trying to make searches for points hard enough that everyone quits. Rewards points must be driving them to bankruptcy.
BTW anyone else getting repeated account disconnects and having to sign in again the last few days ? Let me guess... have I tried turning it off and on ? ...signed out signed in ? ...cleared my cache ? etc. etc. etc. And is anyone else finding that at least one of the "search Bing for blah blah blah" quests will never complete no matter how many variations of the "search" are tried ? At least my issue with the XBox app points was fixed, mostly, AFTER putting in a ticket. Hmm, didn't they used to auto-send a "how did we do" email ? I don't think I got one this time. Maybe they're now auto-filling them with "AWESOME ! YOU GUYS DID AWESOME ! 11 our 10 !" and saving us the trouble. I used to love my Bing newsfeed, clicking a story and reading it, then the next, and smoothly getting points for it. And randomly doing my own searches and loving it. Then MS lost the thread and that stopped working right, or at all. More and more of the "news" links became Ads, not even advertised as such at first. Same with search results. Nearly useless most of the time. They're driving me and many more to hate Bing searches and making the Rewards program a joke. OK, rant done, time to see if a search will count now. Probably not. Hey ! New game ! Try to get MS Rewards search to count, when it doesn't or the timeout interferes, come here and complain. lol.