Britney Spears Deletes Her Instagram Following Concerning Posts

Britney Spears' Instagram account has once again vanished ... this time on the heels of several posts that have fans concerned -- and her ex-husband Kevin Federline's memoir taking aim at her reputation.

The deactivation appears to have gone down Sunday ... with her page now showing the message, "Profile isn’t available. The link may be broken, or the profile my have been removed."

Her X account, however, remains active.

Fans have been worried about some of Britney's recent social media posts ... including a dancing video after she cryptically referenced her two sons.

Another dancing clip the singer shared in October showed her with bruises and bandages ... which she later explained came from a fall down a set of stairs at a friend's house.

Federline's memoir -- which dropped two weeks ago -- is filled with stories about their marriage, her relationship with their sons, and claims of Britney's bad behavior over the years ... including allegations of drug use and infidelity.

Britney later went on a tirade against Federline, saying she's over his "constant gaslighting" -- adding that anyone who knows her understands he's just trying to cash in on salacious gossip.