can we share user login in 2 wordpress installs in 2 subdomains on one server? [duplicate]

See my answer on this exact problem. Long story short, you also need to define COOKIEHASH, otherwise the login cookie names will be different for each site:

define( 'COOKIEHASH', 'randomhash' );

Make sure to change randomhash to a real hash, you can grab one here.

Related Posts:

  1. PHP – setcookie(); not working
  2. How to share cookies and sessions between domain and subdomain?
  3. Is it possible to transfer a WordPress session to a different browser via query string?
  4. How does REST API cookie authentication work in WP 4.7?
  5. Why does it say: ‘Cookies are blocked or not supported’?
  6. Place a cookie when a specific page has been viewed?
  7. How to detect a user that is not logged in
  8. How to change cookie name
  9. Using wp_set_auth_cookie for custom user account system
  10. Should wordpress_logged_in cookie exist while logged out?
  11. WP_Http_Cookie destroys cookie value through urldecode()
  12. Worpdress PHPSESSID / EU law
  13. Get restrict content by submitting Gravity Forms
  14. Website Loads Twice Unnecessarily
  15. Do I use cookies?
  16. How to transition cookies from .subdomain.domain.com to .domain.com with minimal impact on users?
  17. Hide/Show content based on cookie
  18. ERROR: Cookies are blocked or not supported by your browser
  19. What is cookie “U” from domain “.adsymptotic.com” found on the WordPress page? [closed]
  20. Serving Cookies From A Different Domain or Sub-Domain
  21. How to fix samesite attribute in wordpress for chrome errors?
  22. Secure wordpress_logged_in cookie
  23. 2 wordpress blogs with 1 users table and 1 login
  24. Deleting cookie to logout
  25. Show greetings on first time visitors?
  26. Unset a Cookie on Successful Gravity Forms form Submission [closed]
  27. How set a cookie from PHP and get it without refresh
  28. Why wordpress cookies name contains HASH
  29. Cookie only detected when visitor is logged in
  30. Change the user is logged in cookie name
  31. Disconnect automattically after X minutes
  32. background/font size change and remember
  33. WordPress cookies
  34. Modifying request $_COOKIE
  35. Block google maps from loading until user agrees to cookies with Elementor
  36. Need help setting cookies with multiple value [closed]
  37. Enable WordPress to share cookies between domain.com and sub.domain.com
  38. Setting Cookies
  39. How I can share cookies from my dimain to subdomain?
  40. How to setup cookie free domain for wp-includes?
  41. WordPress authentication cookie and ajax calls
  42. COOKIE_ID with username appended
  43. Setting Cookies For Form Autofill
  44. What are your thoughts on overriding the PHP builtin setcookie() function to control whether or not WP creates cookies
  45. How to make use of Transient API as cookie
  46. Issues with set cookie
  47. Accept or deny cookies – how to?
  48. How to set a Cookie-Free Domain with WordPress?
  49. Is it possible to use cookie-free domains in WordPress?
  50. Passing cookies when using wp_remote_get
  51. Setting cookies in WP REST API requests
  52. Detect if authentication is set to “remember” a user being logged on
  53. Store value in cookie
  54. Set Short Automatic Logout Time for One User
  55. WordPress Post Voting – Vote once per IP on entire site
  56. How to change WordPress cookies to be session-only
  57. wordpress can’t read a cookie?
  58. Do I need a Cookie consent on a basic WordPress site?
  59. Page specific cookie
  60. will creating a static folder in the root directory serve the purpose of loading the static content from cookieless domain?
  61. Set cookie with taxonomy name
  62. Best method to show modal only once
  63. Cookie with referral URL [closed]
  64. How to keep a variable in COOKIE or GET query string?
  65. Cookie Details Requested
  66. Cookies in template
  67. Cookie error. No possibility to define my cookie
  68. Favicon not loading until cookies are accepted?
  69. can you help review CCCP (Conditional Cookie Content Post) and help to create a block?
  70. COOKIE_DOMAIN chaos
  71. Setup cookie on Chrome even without HTTPS
  72. PHP cookie control does not work correctly
  73. How can I get an updated cookie in header.php?
  74. Setting a Custom Cookie in WordPress only for Logged In Customer/User (non-admin)
  75. How are sites using wordpress hiding wordpress cookies that have “wp” or “wordpress” in the cookie name?
  76. Correct user session/cookie handling with external site connection in wordpress
  77. Checking for cookies returns correct result only inside Elementor Editor
  78. How to save history in the client’s browser without login? [closed]
  79. Automatically Log Out UserX when visiting WooCommerceStore
  80. Entirely Cookieless WordPress?
  81. is_user_logged_in() returns different values on different pages
  82. When ever wordpress home page refreshes the code is not reading the cookie as set anymore
  83. http_referrer issue when detecting where site comes from and allow if from allowed host
  84. detect referr page
  85. Looking to load a different template part on every load/refresh
  86. Cookie is not set
  87. Capture and display users name
  88. Why isn’t my cookie setting in my function?
  89. WordPress wp-login.php cookie error (WordPress Version 4.2.9)
  90. Logged In cookie gets saved but not Auth cookie
  91. set cookies or let system know a user has been on site
  92. setcookie not working when defined with ‘/’ but working if not defined
  93. How to use Cookie or Session php for one page and just a password
  94. How to get the id dynamically to store cookies
  95. WordPress keep logged in after browser close
  96. Passing Additional Parameters to add_filter Callable
  97. Set cookie using GET variable
  98. How to resolve error “Cookies are blocked due to unexpected output.”?
  99. Session Expired when WordPress Address (URL) and Site Address (URL) are different
  100. WordPress Plugin: Where should I put my cookies for cURL?
error code: 523