If apply online, the system has tendency to reject, so better submit manually. If already submitted manually and still rejected, then write to MBB to take out a bit of your conventional card’s limit to the Ikhwan card. I assume you already have MBB conventional cards.

Because you already hold Maybank (Conventional) credit cards so most likely Maybank Card Centre won't give you a fresh credit line for Maybank Islamic credit cards.

Request Card Centre to convert part of your existing credit card (conventional banking) to Islamic.
Eg existing Conventional RM50000
Say convert RM10000 to Islamic, then Maybank (Conventional) RM40000 and Maybank Islamic RM10000 (for Ikhwan cards)

Nice, thanks for the feedback. Hapeng for your reference but I feel email is more convenient, so you could choose your preferred way.