Hello! My name is Mustafa, and I am an Independent Advisor as well as a long-time Microsoft user. I'm sorry that you are experiencing this issue, and I am hopeful that I will be able to help you find a satisfactory solution.
Can you share other files from Word?
When did this issue start happening?
can you share the same file with other people?
Are you using an organization account? if yes then it could be that your admin is preventing you from sharing this file.
Are you trying to share this file with people from outside your organization? because you will need a different kind of permission to do so
If none of the above is the case then a quick solution would be to copy everything from that file and paste it into a new file and then share it.
Please let me know if this doesn't work or if you need further assistance.
Warm Regards,
Mustafa