Hello,
Try this:
1. Increase PHP Memory limit https://wordpress.org/support/topic/fatal-error-allowed-memory-size-6?replies=13#post-1017842
If this doesn’t fix your problem try:
2. Check your .htaccess file, and try default WP content (save copy of your original htaccess content first)
3. Try to switch theme using FTP
4. Try to turn off all your plugins using FTP
Hello,
Often, this is .htaccess related.
Try to open and delete content of your .htaccess file (ofcourse, first create a backup).
Now, add default wordpress htaccess content -https://codex.wordpress.org/htaccess [ Short link expanded, don’t use them here. ]
Try to login.
