This was addressed elsewhere, but I am repeating it here for anyone else with this question.
It is not possible to create new accounts on the Singularity server. Account can only be copied to Singularity from Tranquillity during the ‘server mirror’ process that is done every 3-4 months. The last mirror completed on February 15, 2021, using data from earlier in that month (on or before February 12). If your EVE Online account was created on or after the mirror capture date (the previously mentioned approximate date of Feb 12), you will not be able to access the Singularity server until the next mirror.
The next mirror will probably be before the end of June. It could be in May. It could be in July. There are not fixed dates for this process; CCP does them based on their testing needs.