Kitchen under-sink RO tank will not fill following a toilet repair

AquaTru undersink RO system in kitchen, 6 months old, was working fine until I replaced a leaking water supply shutoff valve going to a bathroom toilet.

During toilet repair, I shut off main house water supply, opened a bathroom sink faucet and shower faucet, replaced the toilet supply shutoff valve, turned the main house water supply back on, shut off all faucets. Other than some air spurting in the line occasionally at the kitchen sink, there have been no other problems. Water pressure at all faucets appears normal. Yet, RO tank will no longer fill.

Any ideas on how to fix?

Thank you!