A LinkedIn account restricted for no reason almost always has one. The notice just does not spell it out. LinkedIn's help page on account restrictions names causes such as content, a profile, or an identity that breaks its policies, and signs that someone else took over the account. For a restriction on invitations, LinkedIn support will not tell you which cause applied.
So the useful question is which kind of restriction you have, because each has its own way back.
Which kind of restriction you have
LinkedIn asks you to verify your identity. The cause is identity, or signs of a takeover. Log in yourself, follow the steps on screen, and change your password.
A notice names a post, a message, or your profile. The cause is content or a profile that breaks its policies. Read what the notice names and follow its steps. Some suspensions end by themselves at the time the notice gives.
Only your invitations stopped, and the rest of LinkedIn works. That is an invitation restriction, not an account restriction. It lifts on its own, and the LinkedIn weekly connection limit, with sources is the page for it.
A second restriction soon after the first. LinkedIn warns that repeated suspensions can end in a permanent restriction.
How to read the planner
The planner cannot read your notice, so it cannot name your cause. What it does is tell you what to do next. With a restricted account picked, it gives no weekly plan at all, only LinkedIn's advice to stop and the help page that advice rests on.
Say instead that you saw a limit notice, and the result becomes a pause with LinkedIn's wait for that case. Only tell it there were no recent notices once LinkedIn has lifted the restriction.
When the restriction lifts
Come back slower than you left. Send fewer invitations than before, invite people likely to know you, and withdraw the oldest pending invitations one at a time. LinkedIn names invitations that are often ignored or left pending among its reasons for stopping an account's invitations.
Then run the planner again for your own account. It gives a conservative weekly number to start from, and a source for each step.