Database error – WP Users Integration

[testtomartin2025]

I’m getting the error “Database error: Illegal mix of collations (utf8mb4_unicode_ci,IMPLICIT) and (utf8mb4_unicode_520_ci,IMPLICIT) for operation ‘='” When I try to use the “Link subscribers with users by email” on the plugin WP Users Integration

Is a new installation of the two plugins Newsletter + WP Users Integration

[Stefano]

This is because your DB table has a different collation. It happens when the DB is updated and you have tables created before and after that update.
You can ask the provider to uniform the collation of all the tables using the “convert” MySQL command and convert them to “utf8mb4_unicode_ci”.
Nothing will happens to you data, is only the way tests are compared.

[Stefano]

It’s worth saying, that a backup is recommended!
I don’t know if there is a plugin that does that operation, I’ll try to look for it.

[testtomartin2025]

Hi Stefano,

I changed the rows on the user table to utf8mb4_unicode_520_ci and the link button worked.

(I choose utf8mb4_unicode_520_ci because the majority of the tables are set to utf8mb4_unicode_520_ci and it is the new standard)

Thank you.

[Author]

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