Problem with permalinks settings – generates errors on internal pages

Hello,
I have a problem with permalinks settings.
When set to Plain – https://mwtradehouse.com/?p=123 there is no problem. But when I set them to Post name – https://mwtradehouse.com/sample-post/ a conflict occurs and generates the following errors:

Warning: preg_match(): Compilation failed: quantifier does not follow a repeatable item at offset 1 in /home/kpmt/mwtradehouse.com/wp-includes/class-wp.php on line 223

Warning: preg_match(): Compilation failed: quantifier does not follow a repeatable item at offset 1 in /home/kpmt/mwtradehouse.com/wp-includes/class-wp.php on line 224

Warning: preg_match(): Compilation failed: quantifier does not follow a repeatable item at offset 1 in /home/kpmt/mwtradehouse.com/wp-includes/class-wp.php on line 223

Warning: preg_match(): Compilation failed: quantifier does not follow a repeatable item at offset 1 in /home/kpmt/mwtradehouse.com/wp-includes/class-wp.php on line 224

These errors appear on all internal pages.

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