Problem:
WordPress found a fatal database error on the Website that looks this way:
COLLATION ‘utf8_general_ci’ is not valid for CHARACTER SET ‘utf8mb4’
Solution:
The reason for this issue is that various database tables use a different collations.
To solve the issue a matching and similar collation for all DB tables.
You can run the following MySQL query to solve such an issue, but it will need to be adjusted with the matching table prefix and also in case a different collation is used than mentioned inside the query:
ALTER TABLE wp_posts CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_520_ci;
