If people are saying they can't follow you on Twitter, there may be several reasons why.
By default, all Tweets you send out are public - that is, anyone can see them. Twitter allows users to set their account as protected, which means that only approved followers can see their Tweets. Furthermore, new followers must be approved by the account owner.
Double-check that your account is not protected by going to your account settings and selecting 'Public' under the Privacy and Safety heading. Then, check your Notifications. If your account was protected, you may have a backlog of requests from other Twitter users to follow you.
If you block a Twitter user, they will not be able to follow you. For awhile, block lists were common on this platform. Users could export and import lists of certain accounts, allowing Twitter users to block hundreds of people quite easily.
Twitter has since disabled the ability to import block lists, but the actual blocks remain. Go to your Privacy and Safety settings, and double check that you did not accidentally block the person trying to follow you.
Twitter limits both the number of total followers, and the amount of people you can add per day. Check the account of the person trying to follow you. If they already follow 5,000 other accounts, or have added 400 accounts today, they may be at their limit (note that these numbers are subject to change by Twitter).
Ask the person trying to follow you to unfollow a few other accounts, or to try again tomorrow.
If your follower count looks off, some of the accounts who followed you awhile ago may have been disabled due to bot-like activity. Even human-owned accounts can sometimes get unfairly accused of being a bot, which means that Twitter restricts how they are able to use the site.
If someone is trying to follow you but can't, have them contact Twitter Customer Service. They may need to have their account verified (the 'blue check mark' you seen on some accounts) before they can follow you.
If all else fails and you cannot solve this problem on your own, contact Twitter Customer Service yourself. Try to explain the problem as best you can. Take screen shots if you're able. They will be able to set your account up so that you can start adding new followers.
After thousands of Twitter customers came to GetHuman in search of an answer to this problem (and many others), we decided it was time to publish instructions. So we put together Why Can't People Follow Me on Twitter? to try to help. It takes time to get through these steps according to other users, including time spent working through each step and contacting Twitter if necessary. Best of luck and please let us know if you successfully resolve your issue with guidance from this page.
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