Cannot move any piece

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HKPP
I cannot move any piece in SOME games. 5th time since 1 wk. Never happened before. I can chat, resign but NOT move anything (obviously, being possible). Just now, for example. In iPhone 6. Any feedback? (Using chess.com for >1yr, this is new).
HKPP
Just a note: Both in 1 min and 3 min games. Internet WORKING.
HKPP
It happened again twice. 😡