What is the ruling of Islamic law regarding gatherings in praise of the Messenger of Allah, peace and blessings be upon him (Mawlid celebrations), in which "O Messenger of Allah, O dispeller of worry and distress" is recited?

Praising the Prophet, peace and blessings be upon him, and commending him is permissible and good, as long as it does not include any religious prohibition, such as exaggeration in description that is only befitting of Allah. The Prophet, peace and blessings be upon him, forbade this, saying: "Do not exaggerate in praising me as the Christians exaggerated in praising 'Isa the son of Maryam. Verily, I am only a slave, so say: 'Allah's slave and His Messenger.'" Likewise, it is not permissible to praise him, peace and blessings be upon him, with knowledge of the unseen. The conclusion is that praising him, peace and blessings be upon him, is good, as long as it does not involve exaggeration or falsehood. As for celebrating mawlids (birthdays), that has been answered previously.