Troubleshooting issues related to Activity Feed

In Activity Feed, while adding an attachment, following error is displayed:

Attachment creation failed. Please try again later" or "Attachment creation failed. Please try again later : API_CURRENTLY_DISABLED: API is disabled for this User.

1. Open the Setup > Manage Users > Profile page.
2. Select profile for which permissions are required to be updated and then click Edit.
3. In the Administrative Permissions section, select API enabled.

While adding attachment in send email screen from activity feed, following error is displayed:

Attachment creation failed. Please try again later" or "Attachment creation failed. Please try again later : insufficient access rights on cross-reference id.

1. Open the Setup > Manage Users > Profile page.
2. Select profile for which permissions are required to be updated and then click Edit.
3. In the Custom Object Permissions section, for Temporary Attachment Select check boxes for Read, Create, Edit and Delete permission.

While sending an email, following error is displayed:

NO_MASS_MAIL_PERMISSION, Single email is not enabled for your organization or profile.

1. Go to Setup > Email Administration > Deliverability.
2. In the section Access to Send Email (All Email Services), select All email option from the Access Level list.