Hello!

With MathML in user preferences activated I just get an error in the formulas in this article: https://ca.wikipedia.org/wiki/Matriu_de_rotaci%C3%B3

Full error tag:
No s'ha pogut entendre (MathML si és possible (experimental): Resposta invàlida ('Math extension cannot connect to Restbase.') del servidor '/mathoid/local/v1/':): {\displaystyle \begin{pmatrix} \cos \theta & -\sin \theta \\ \sin \theta & \cos \theta \\ \end{pmatrix} }

English translation: "Cannot understand (MathML if possible (experimental): Invalid response"