I'm getting some error messages

Twitter sends a confirmation code or an error message to every action made through the Twitter API. Circleboom logs these messages, but they might not be shown to you during fast follow actions.

You are unable to follow more people at this time.

Twitter sends this error message along with a URL to this Help Center article when;

Your account may be locked or limited.
You may have hit a follow limit.

These limits are clearly defined in their documentation as follows;

Every account can follow 5,000 accounts total. Once you’ve followed 5,000 accounts, there are limits to the number of additional accounts you can follow. This number is different for each account and is based on your ratio of followers to following; this ratio is not published. Follow limits cannot be lifted by Twitter and everyone is subject to limits, even high profile and API accounts.

Every Twitter account is able to follow up to 400 accounts per day. Verified Twitter accounts are able to follow up to 1,000 accounts per day. in addition to the account-based limits above. Please note that this is just a technical limit to prevent egregious abuse from spam accounts.

Accounts are also prohibited from aggressively following other accounts.

The limits are defined by Twitter. If their AI decides you’re following/unfollowing aggressively, she may slow things down for an uncertain period of time. When this happens, Twitter API sends a “you’re not allowed to follow more” error even you’re not followed 400 for that day. If you wait a little bit, she opens the door again to see how you’ll behave.

You have exceeded the Twitter error limit. Please wait a little bit more to try it again.

After getting a certain number of Twitter error messages, Circleboom prevents you from making more requests to prevent your account from getting locked or suspended.

If you're getting this error, call it a day and give it a break. When you try after a while, you'll be able to do follow and unfollow requests through the Twitter API.

To protect our users from spam and other malicious activity, this account is temporarily locked.

Twitter locks or suspends users’ account time to time when they do an aggressive follow churn as mentioned on Circleboom and Twitter Rules https://help.twitter.com/en/using-twitter/twitter-follow-limit

That means, when a user follows too many users in a short time period or unfollows them faster than an average Twitter user, Twitter marks the user for a period to close-watch him/her for follows/unfollows across the Twitter ecosystem including all 3rd party apps like Circleboom, Twitter mobile apps, and websites.

Please log in to https://twitter.com to unlock your account.

You have been blocked from following this account at the request of the user.

When you try to follow a Twitter account that blocked you earlier, Twitter sends this error message to inform you. Circleboom logs these messages but they might not be shown to you during fast follow actions.

To learn more about "Being Blocked", please refer to Twitter's related article here.

Invalid or expired token.

This might happen when;

You try to follow/unfollow after getting "you are unable to follow more people at this time" error, Twitter may think that someone or some apps are using your Twitter account in a harmful way, and may invalidate your Twitter account's tokens (authentication info) to protect your account from being abused by 3rd party systems and expects you to re-login.
Your browser has a "Do not track me" feature on it. It may stem from several Twitter authentication issues including the "invalid or expired token" error Twitter sends and blocks your follow/unfollows requests if it is open.
The App’s permissions revoked on Twitter. Please check https://twitter.com/settings/applications page if our app named "Circleboom” still got access. If it is revoked by mistake, it prevents Circleboom to fulfill your requests on behalf of you.
Your account may be temporarily suspended and/or blocked doing any follows/unfollows by Twitter due to aggressive usage.
Your computer's time is not synced properly. Please sync your time with the internet time.

Windows Users: Set your server to "time.nist.gov"

How to check your Twitter Apps

Getting "Somehow your Twitter token is expired or invalidated..." message

Pro Tip: Check your Twitter apps to see if there any other third-party and possibly unreliable apps and revoke their permissions every once in a while to protect your Twitter account and your reputation.