Login issues on WordPress Multisite and domain mapping

Question

I'm having issues with a WordPress Multisite subsite where I can't log in - I get this error:

ERROR: cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.

I have researched a lot and tried various fixes to no avail. However I saw this post that said it was resolved by removing sunrise.php which was an older way of domain mapping before it was added to core.

When I remove sunrise.php I can't access sites by entering anything other than the full URL. if I enter domain.com instead of https://www.domain.com it redirects to my main site with a message saying "registration is disabled".

I know these two things may be separate questions, but I'm feeling they are linked, in that I appear to be having issues related to domain mapping.

If anyone has experienced either of these issues, or both(!), any tips would be appreciated.

Answer 1

I followed the instructions in the post I mentioned and that resolved the cookies error on logging in - but as I mentioned the sites would now not resolve using non-www. Subsites redirected to a registration page. This turned out to be an issue with htaccess file, but on adding the required rules the subsites still redirected to main site for non-www.

It turned out, based on previous (incorrect?) advice I had the www in Site Address (URL) Sites -> Edit Site -> Info.

I removed www from this setting. Now the sites were available wether you typed in www or not - but it always resolved to the non-www url.

Then I went into Sites -> Edit Site -> Settings and changed the Siteurl and Home address to be with www.

I had previously read that all three settings should be the same, but this is the only method that worked for me if I wanted www url to be the primary url and for both www and non-www to be available.

I would love to hear what people's thoughts on this are - or what methods you are using to domain map on multisite with www as primary.