Most common issue with users is Access Denied on SharePoint sites. If you have configured Request Access settings on site, users can Request Access to site by simply clicking on “Request Access” link on Access denied page/Pop Up. This simply triggers email to site owner who then can grant access to users.
But if owner of the site granted users permission on site and users still cannot login to site, you can go through following steps to resolve the issue.
Check step by step -->
Step 1 Check User Permission on Site
Check if user has access to site by visiting site permissions. In site permissions you can use “Check Permissions” page to check where user has access, to check permissions use user’s login ID or email ID. If the user doesn’t have sufficient permission you can grant it
Step 2 Check group permission to which user belong
Check the group permission and setting to which user belongs, especially when your site is having unique permissions
Step 3 Check if all resources are checked in and have published version i.e. they are not checked out. Check all master pages, CSS, Images other related files etc.
This is the common mistake which is done by SharePoint Site owners and Designers, check if all master pages and CSS files related to that are checked in and have major published versions. If any file don’t have major published version in SharePoint it will not be visible to readers and Viewers, but same files will be visible to Owners and contributors who have rights to read minor versions. So please double check if you have major version to all files especially in SharePoint publishing site.
Step 4 Check all images and style resources are having access to all users
If you are referring any images or flash files on SharePoint page please be sure that these are accessible to all users and at least read permission is there. The best way to use images on pages it to place the images in Layouts images folder. However this is not possible for end users and administrator access is required on server to place these files or to run deployable solution of images on server.
Step 5 Check Document library and List level permissions
Many times Document libraries and lists have unique permissions and it is not necessary that the rights you have on SharePoint Site/Web will be same on Document library/ Lists. So please double check if user /group have appropriate rights.
Step 6 Check Item level permissions if still not able to access
Same as step 5 but for Folders and list Items.
If all of above doesn't solve the access denied issue and user still struggling to access site there might be something went wrong with user account in SharePoint database. To solve this you can go through final step (Step 7) which is to delete user account from site collection and add again.
Step 7 something went wrong with User Account
And finally if all of above is good and still user getting access denied?
Please delete the user from site collection and add again to it. It will solve your problem about access denied if all above steps are checked
To delete the user from site collections please go to http://<SiteCollection>/_layouts/people.aspx?MembershipGroupId=0 and select the user and delete
Please add user again to desired group with proper permissions
And now if you check user should be able to login to SharePoint site without any issues
